Image display device, display panel, and terminal device

ABSTRACT

A subpixel  4 S has a parallelogram aperture, which is equivalent upon rotation by 180 degrees in a XY plane and asymmetric about a line R-R′ or L-L′ parallel to the Y-axis and passing through the center Or or Ol of the subpixel. The subpixels  4 S adjacent to each other in the X-axis direction in a unit of display  4 U are point-symmetric about the center Ou of the unit of display  4 U. The apertures of a right-eye pixel  4 R and left eye pixel  4 L have the centers Or and Ol around the intersections of the diagonals of their respective parallelograms, respectively. The centers Or and Ol are shifted from a line E-E′ to be away from each other in the Y-axis direction.

INCORPORATION BY REFERENCE

This application is based on Japanese Patent Application No. 2011-094541filed on Apr. 20, 2011, and including specification, claims, drawingsand summary. The disclosure of the above Japanese Patent Application isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to an image display device, display panel,and terminal device, and particularly to a device for displayingdifferent images intended for multiple observing points or a displaypanel structure for displaying three-dimensional images in high quality.

BACKGROUND ART

As cellular phones and information terminals have been advanced, imagedisplay devices become smaller and finer. On the other hand, as newvalue-added image display devices, attention has been drawn to imagedisplay devices allowing an observer to view different images dependingon an observing point, namely image display devices with which differentimages are visible at multiple observing points, and tothree-dimensional image display devices displaying different images asparallax images so that the observer can view a three-dimensional image.

A known technique of providing different images to multiple observingpoints merges and displays image data for different observing points ona display panel, separates the displayed composite image by an opticalseparating unit such as a lens and a barrier having slits (screen), andprovides the images to individual observing points. The images can beseparated by an optical unit such as a barrier having slits and a lensso as to limit the pixels to be seen from each observing point. Aparallax barrier comprising a barrier having many slits in a stripepattern or a lenticular lens comprising an array of cylindrical lenseshaving lens effect in one directional is generally used as the imageseparating unit.

A three-dimensional image display device employing an optical imageseparating unit is suitable for installing in terminal devices such ascellular phones because it does not require an observer to wear specialglasses and eliminates annoyance of wearing glasses. Cellular phonescarrying a three-dimensional display device comprising a liquid crystalpanel and a parallax barrier have already been commercialized (forexample, see “NIKKEI Electronics, No. 838,” Nikkei Publishing, Jan. 6,2003, pp 26-27).

The above technique, namely a three-dimensional image display deviceproviding different images to multiple observing points using an opticalseparating unit sometimes causes an observer to see a dark boundarybetween images as his/her observing point is shifted and the viewedimage is switched. This phenomenon occurs when a non-display regionbetween pixels for different observing points (a shielding unitgenerally called a black matrix in a liquid crystal panel) is viewed.This phenomenon accompanying shift of the observing point of theobserver does not occur with a general three-dimensional display devicewithout an optical separating unit. Therefore, the observer experiencesdiscomfort or senses deterioration in the display quality from the abovephenomenon occurring with a multiple observing point three-dimensionaldisplay device or three-dimensional display device with an opticalseparating unit.

This is a phenomenon generally called 3D moire. The 3D moire is aperiodically appearing uneven luminance (sometimes referred to as unevencolor) caused by displaying different images in different angulardirections. Furthermore, the 3D moire is luminance angular fluctuationand large luminance angular fluctuation has adverse effect onthree-dimensional observation.

In this specification, periodically appearing uneven luminance(sometimes referred to as uneven color) caused by displaying differentimages in different angular directions, particularly luminance angularfluctuation is defined as “3D moire.” Generally, fringes appearing whenstructures different in periodicity interfere with each other are called“moire fringes.” The moire fringes are interference fringes appearingdepending on the periodicity or pitch of structures. On the other hand,the 3D moire is uneven luminance caused by the image-forming property ofan image separating unit and seen from a specific position. Therefore,the 3D moire is distinguished from the moire fringes in thisspecification.

In order to ameliorate the above problem caused by an optical separatingunit and shielding unit, three-dimensional image display devices inwhich the shape and geometry of pixel electrodes and shielding unit ofthe display panel is designed to reduce deterioration in the displayquality have been proposed (for example, Unexamined Japanese PatentApplication KOKAI Publication No. 2005-208567; Patent Literature 1,hereafter and Unexamined Japanese Patent Application KOKAI PublicationNo. H10-186294; Patent Literature 2, hereafter).

In the display device disclosed in the Patent Literature 1, as shown inFIG. 33, in a cross-section of the display panel in the verticaldirection 1011 perpendicular to the direction of the array ofcylindrical lenses 1003 a, the ratio between the shielding unit (thewiring 1070 and shielding unit 1076) and aperture is nearly constant atany point in the horizontal direction 1012.

Therefore, even if the observer shifts his/her observing point in thehorizontal direction 1012, which is the image separation direction, soas to change the observing direction, the ratio of the shielding unitviewed is nearly constant. In other words, it does not happen to theobserver to see only the shielding unit in a specific direction or tosee a darker display. Then, deterioration in the display quality causedby the shielding region is prevented.

The three-dimensional display device disclosed in the Patent Literature2 has the pixel layout as shown in FIG. 34A and pixels as shown in FIG.34B. In the three-dimensional display device disclosed in the PatentLiterature 2, the total aperture width in the Y-axis direction ofadjacent pixels is constant throughout an overlapping region 1013 andequal to the aperture width in the Y-axis direction in a rectangularregion B. Therefore, the three-dimensional display device disclosed inthe Patent Literature 2 can provide substantially uniform luminancecontinued in the horizontal direction and maintain substantiallyconstant luminance in the X-axis direction.

Therefore, when the same image is output to adjacent columns of pixels,the three-dimensional display device disclosed in the Patent Literature2 can maintain constant luminance while the observer's line of sightcrosses the boundary between windows.

In prior art three-dimensional image display devices, pixel structuresin which the aperture width is constant or nearly constant in the imageseparation direction as described above have been proposed. However, itwas found that some production problems with the image separating unitleads to some issues on the three-dimensional display performance whenthe pixel structures disclosed in the Patent Literature 1 and PatentLiterature 2 are used. The details are as follows.

Three-dimensional image display devices conventionally employ theabove-mentioned parallax barrier or lenticular lens as a unit foroptically separating images. A prior art lenticular lens has aperiodically repeated structure in which the convex parts of cylindricallenses and the concave parts between cylindrical lenses are adjacent toeach other. Techniques for producing such a lenticular lens includemolding using a die, photolithography, and inkjet.

However, with any technique being applied to production, there will bedifference in processing accuracy between the convex part and concavepart of a lens. Particularly, with a prior art lenticular lens, it iseasier to produce the convex part in a given shape in a stable mannerthan the concave part. Then, the concave part is subject todeterioration in optical separation performance. For example, in thecase of molding a lens using a die, the die is steeper and pointed inshape at the lens concave part than at the lens convex part. Not onlythe shape stability during molding but also the pressurizing duringshaping contributes to the concave part having a lower level of shapestability than the convex part. Furthermore, even when a wet processsuch as an IJ technique is used to create a lens, the droplet boundarycorresponds to the concave part and it is difficult to ensure the shapestability. Additionally, various factors including difficulty ofremoving unpeeled residues and/or adherent foreign substances from thelens concave part compared with from the lens convex part cause localdeterioration in optical separation performance at the concave part.

In the region where the optical separation performance is deterioratedas described above, light emitted from the aperture of a pixel cannot becontrolled by the image separating unit. Light emitted from the imageseparating unit under no control of the image separating unit results ina video image for one observing point being mixed with a video image foranother observing point, which adversely affects the three-dimensionaldisplay. Particularly, when a mixture ratio between a video image forone observing point and a video image for another observing pointexceeds a given value, the observer feels discomfort and has difficultyin three-dimensional observation. Furthermore, as the region of whichthree-dimensional observation is difficult because of mixture of a videoimage for one observing point and a video image for another observingpoint is enlarged, the proper three-dimensional observation range isnarrowed; the three-dimensional display performance is lowered.Therefore, in this specification, mixture or leakage of a video imagefor one observing point and a video image for another observing point isdefined as “3D crosstalk.” In this specification, the term “crosstalk”is used to refer to deterioration in the image quality due to electricleakage of video image signals and/or scan signals and distinguishedfrom the “3D crosstalk.”

Among other optical separating unit, there is a GRIN (gradient index)lens, which is an electro-optic element using liquid crystal. Even withthe use of a GRIN lens, the refractive index profile is more uneven atthe lens concave part than at the lens convex part because of therelationship between electrode positions and electric field. Therefore,like the above-described lenticular lens, the optical separationperformance at the lens concave part deteriorates.

Even with the use of a parallax barrier having slits, if the accuracy ofprocessing the electrode end forming slits largely varies, the shieldingperformance at the slit end will become more uneven. Consequently, theimage separation performance locally deteriorates, lowering the imagequality.

Hence, it is difficult not only for a lenticular lens but also for anyknown image separating unit to achieve uniform optical separationperformance. It is costly to obtain an image separating unit havingcompletely uniform optical separation performance with the use of highlyaccurate processing techniques. When the pixels disclosed in the PatentLiterature 1 and Patent Literature 2 in which the aperture width isconstant in the image separation direction are used, some profile ofoptical separation performance of the image separating unit disturbscontrol over 3D moire and 3D crosstalk, deteriorating thethree-dimensional display performance. Light delivered by high opticalseparation performance regions will easily be subject to 3D moire due toslight variation in the processing accuracy. Light delivered by lowoptical separation performance regions will be responsible for increased3D crosstalk, narrowing the three-dimensional observation range. Inregard to the above problems caused by the optical separationperformance profile of the optical separating unit and the pixelstructure, the techniques disclosed in the Patent Literature 1 andPatent Literature 2 encounter difficulty in accomplishing a designcontrolling both 3D moire and 3D crosstalk, failing to control both 3Dmoire and 3D and balance them.

The 3D moire may not be a problem at some observation positions.However, large luminance angular fluctuation presumably has some adverseeffect on three-dimensional observation. Therefore, it is desirable thatthe fluctuation in luminance is equal to or lower than a given value.Furthermore, it is desirable that the magnitude of 3D crosstalk is equalto or lower than a given value.

SUMMARY

The present invention is invented in view of the above circumstances andan exemplary object of the present invention is to provide an imagedisplay device, display panel, and terminal device having influence of3D moire minimized, 3D crosstalk reduced, and improving thethree-dimensional display quality.

In order to achieve the above object, the image display device accordingto a first exemplary aspect of the present invention includes:

a display panel in which units of display including at least a pixeldisplaying a first observing point image and a pixel displaying a secondobserving point image are arranged in a matrix; and

an optical distributer for distributing light emitted from the pixeldisplaying the first observing point image and pixel displaying thesecond observing point image in directions different from each other ina first direction, wherein

the pixel displaying the first observing point image and pixeldisplaying the second observing point image are adjacent to each otherin the first direction;

the units of display are arranged in rows extending in the firstdirection and in columns extending in a second direction perpendicularto the first direction;

a shielding unit is provided around an aperture of the pixel displayingthe first observing point image and an aperture of the pixel displayingthe second observing point image;

the aperture of the pixel displaying the first observing point image andaperture of the pixel displaying the second observing point imageinclude a first region where the apertures overlap with each other inthe second direction and a second region that is a remaining region;

a total aperture width in the second direction of the aperture of thepixel displaying the first observing point image and aperture of thepixel displaying the second observing point image in the first region isa first aperture width;

an aperture width in the second direction of the aperture of the pixeldisplaying the first observing point image and aperture of the pixeldisplaying the second observing point image in the second region is asecond aperture width;

a third region where two of the units of display adjacent to each otherin the first direction overlap with each other in the second directionis provided, and a total aperture width in the second direction of thetwo units of display in the third region is a third aperture width;

the aperture of the pixel displaying the first observing point image andaperture of the pixel displaying the second observing point image eachcomprises a shape that is at least point-symmetric and notline-symmetric;

centers of the apertures are shifted in the second direction withrespect to a line parallel to the first direction and passing through acenter of the unit of display, and the aperture of the pixel displayingthe first observing point image and aperture of the pixel displaying thesecond observing point image are point-symmetric about the center of theunit of display; and

the third aperture width is different from the first aperture width.

Furthermore, it is possible that the third aperture width is smallerthan the first aperture width.

Furthermore, it is possible that the optical distributer comprises analternate structure at least in the first direction comprising regionsof high separation performance and regions of low separation performancein distributing light from the pixel displaying the first observingpoint image and pixel displaying the second observing point image indirections different from each other; and

the regions of high separation performance extend from the aperture ofthe pixel displaying the first observing point image to the aperture ofthe pixel displaying the second observing point image.

Furthermore, it is possible that the optical distributer comprises alenticular lens sheet in which convex parts and concave parts ofcylindrical lenses are alternately arranged in the first direction; and

the convex parts of cylindrical lenses are provided at positionscorresponding to the first region and the concave parts of cylindricallenses are provided at positions corresponding to the third region.

Furthermore, it is possible that the optical distributer comprises arefractive index distributed lens comprising a pair of substrates withliquid crystal in-between; and

a pair of electrodes provided to the substrates is provided at positionscorresponding to the third region.

Furthermore, it is possible that the pixel displaying the firstobserving point image and pixel displaying the second observing pointimage are subpixels, and the apertures are enclosed by data lines, gatelines and charging capacitor electrodes;

the subpixels of the display panel are arranged in an array of adjoiningpixel pairs each comprising two subpixels provided on either side of oneof the gate lines and adjacent to each other in the second direction asa basic unit;

a switcher of one of the two subpixels and a switcher of the other ofthe two subpixels are controlled by the gate line interposed between andshared by the two subpixels and connected to different ones of the datalines;

one electrode of the switchers forms a capacitor together with thecharging capacitor electrode; and

the charging capacitor electrode is electrically connected to a chargingcapacitor line provided at least in a boundary region between thesubpixels in the unit of display.

Furthermore, it is possible that the pixel displaying the firstobserving point image and the pixel displaying the second observingpoint image are subpixels, and the apertures are enclosed by data lines,gate lines and charging capacitor electrodes;

the subpixels of the display panel are arranged in an array of adjoiningpixel pairs each comprising two subpixels provided on either side of oneof the data lines and adjacent to each other in the second direction asa basic unit;

a switcher of one of the two subpixels and a switcher of the other ofthe two subpixels are connected to the data line interposed between andshared by the two subpixels and controlled by different ones of the gatelines;

one electrode of the switchers forms a capacitor together with thecharging capacitor electrode;

the charging capacitor electrode is provided at least in a boundaryregion between the subpixels of the adjoining pixel pair; and

N charging capacitor lines electrically connected to the chargingcapacitor electrode each crosses at least one of virtual lines parallelto the second direction and dividing a width of the subpixel into N+1equal parts in the first direction at the aperture.

Furthermore, it is possible that the display panel comprises a substrateat least provided with a pair of parallel electrodes and a liquidcrystal layer interposed between the substrate and an oppositesubstrate; and

the pair of parallel electrodes is arranged in the second direction andliquid crystal molecules of the liquid crystal layer are driven by anelectric field created between the pair of parallel electrodes.

Furthermore, it is possible that the pair of parallel electrodescomprises transparent electrodes comprising at least two layers formedwith an insulating film in-between; and

one layer of the transparent electrodes is provided with a slitelectrode.

Furthermore, it is possible that the slit electrode is a transparentelectrode on a side to the liquid crystal layer.

In order to achieve the above object, the display panel according to asecond exemplary aspect of the present invention is a display panel inwhich units of display including at least a pixel displaying a firstobserving point image and a pixel displaying a second observing pointimage are arranged in a matrix, wherein:

the units of display are arranged in rows extending in a first directionin which the pixel displaying the first observing point image and pixeldisplaying the second observing point image are adjacent to each otherand in columns extending in a second direction perpendicular to thefirst direction;

a shielding unit is provided around an aperture of the pixel displayingthe first observing point image and an aperture of the pixel displayingthe second observing point image;

the aperture of the pixel displaying the first observing point image andaperture of the pixel displaying the second observing point imageinclude a first region where the apertures overlap with each other inthe second direction and a second region that is a remaining region;

a total aperture width in the second direction of the aperture of thepixel displaying the first observing point image and aperture of thepixel displaying the second observing point image in the first region isa first aperture width;

an aperture width in the second direction of the aperture of the pixeldisplaying the first observing point image and aperture of the pixeldisplaying the second observing point image in the second region is asecond aperture width;

a third region where two of the units of display adjacent to each otherin the first direction overlap with each other in the second directionis provided, and a total aperture width in the second direction of thetwo units of display in the third region is a third aperture width;

the aperture of the pixel displaying the first observing point image andaperture of the pixel displaying the second observing point image eachcomprises a shape that is at least point-symmetric and notline-symmetric;

centers of the apertures are shifted in the second direction withrespect to a line parallel to the first direction and passing through acenter of the unit of display, and the aperture of the pixel displayingthe first observing point image and aperture of the pixel displaying thesecond observing point image are point-symmetric about the center of theunit of display; and

the third aperture width is different from the first aperture width.

In order to achieve the above object, the terminal device according to athird exemplary aspect of the present invention has the image displaydevice according to a first exemplary aspect of the present inventioninstalled.

The present invention can minimize influence of 3D moire, reduce 3Dcrosstalk, and improve the three-dimensional display quality.

BRIEF DESCRIPTION OF THE DRAWINGS

These objects and other objects and advantages of the present inventionwill become more apparent upon reading of the following detaileddescription and the accompanying drawings in which:

FIG. 1 A plane view showing subpixels of the display panel according toEmbodiment 1 of the present invention;

FIG. 2 A cross-sectional view showing the image display device accordingto Embodiment 1 of the present invention;

FIG. 3 An enlarged view showing subpixels of the display panel accordingto Embodiment 1 of the present invention;

FIG. 4 An enlarged view showing subpixels of the display panel accordingto Embodiment 1 of the present invention;

FIG. 5 A cross-sectional view at the line D-D′ of the display panelaccording to Embodiment 1 of the present invention;

FIG. 6 A cross-sectional view at the line R-R′ of the display panelaccording to Embodiment 1 of the present invention;

FIG. 7] Schematic charts showing the profiles of vertical aperture widthand brightness in a subpixel of the display panel according toEmbodiment 1 of the present invention;

FIG. 8 A cross-sectional view showing an optical model using alenticular lens;

FIG. 9 An illustration showing an optical model with the minimum radiusof curvature for calculating image separation conditions of thelenticular lens;

FIG. 10 An illustration showing an optical model with the maximum radiusof curvature for calculating image separation conditions of thelenticular lens;

FIG. 11 A graphical representation showing an exemplary profile ofluminance in the image display device according to Embodiment 1 of thepresent invention;

FIG. 12 An illustration for explaining the polarities entered in thedata lines upon dot inversion drive in the image display deviceaccording to Embodiment 1 of the present invention;

FIG. 13 An illustration showing the polarities of subpixels in the imagedisplay device according to Embodiment 1 of the present invention;

FIG. 14 A plane view showing the display panel according to Embodiment 1of the present invention;

FIG. 15A A perspective view showing a portable device in which the imagedisplay device of the present invention is installed;

FIG. 15B A perspective view showing a portable device in which the imagedisplay device of the present invention is installed;

FIG. 15C A perspective view showing a portable device in which the imagedisplay device of the present invention is installed;

FIG. 16 A conceptual illustration showing the light collection in theimage display device according to Embodiment 1 of the present invention;

FIG. 17 A conceptual illustration showing the spatial scheme;

FIG. 18 A plane view showing the subpixels of the display panelaccording to Embodiment 2 of the present invention;

FIG. 19 An enlarged view showing subpixels of the display panelaccording to Embodiment 2 of the present invention;

FIG. 20 A cross-sectional view at the line D-D′ of the display panelaccording to Embodiment 2 of the present invention;

FIG. 21 A cross-sectional view at the line R-R′ of the display panelaccording to Embodiment 2 of the present invention;

FIG. 22 An illustration for explaining the polarities entered in thedata lines upon dot inversion drive in the image display deviceaccording to Embodiment 2 of the present invention;

FIG. 23 An illustration showing the polarities of subpixels in the imagedisplay device according to Embodiment 2 of the present invention;

FIG. 24 A plane view showing the display panel according to Embodiment 2of the present invention;

FIG. 25 An enlarged view showing subpixels of the display panelaccording to Embodiment 3 of the present invention;

FIG. 26 An enlarged view showing subpixels of the display panelaccording to Embodiment 3 of the present invention;

FIG. 27 A cross-sectional view at the line D-D′ of the display panelaccording to Embodiment 3 of the present invention;

FIG. 28 Across-sectional view showing the image display device accordingto Embodiment 4 of the present invention;

FIG. 29 Across-sectional view showing the image separating unitaccording to Embodiment 4 of the present invention;

FIG. 30 An enlarged view showing subpixels of the display panelaccording to Embodiment 5 of the present invention;

FIG. 31 A cross-sectional view at the line F-F′ of the display panelaccording to Embodiment 5 of the present invention;

FIG. 32 An enlarged view showing subpixels of the display panelaccording to a modified embodiment of Embodiment 5 of the presentinvention;

FIG. 33 A plane view showing pixels of a prior art three-dimensionalimage display device;

FIG. 34A A plane view showing pixels of a prior art three-dimensionalimage display device; and

FIG. 34B A plane view showing pixels of a prior art three-dimensionalimage display device.

EXEMPLARY EMBODIMENTS

Image display devices according to embodiments of the present inventionwill be described hereafter with reference to the drawings.

EMBODIMENT 1

An image display device according to this embodiment, display panel tobe installed in the image display device, terminal device in which theimage display device is installed, and driving method thereof will bedescribed hereafter.

As shown in FIGS. 1 and 2, an image display device 1 according to thisembodiment comprises a display panel 2, a lenticular lens 3, and abacklight 15. The display panel 2 is an electro-optic element usingliquid crystal molecules and a display panel having pixels 4P arrangedin a matrix. The lenticular lens 3 is placed on the display surface sideof the display panel 2, namely the side closer to an user. The backlight15 is placed on the back of the display panel 2.

As shown in FIG. 1, units of display 4U, 4U′, 4U″, and 4U″′ are arrangedin a matrix in the display unit of the display panel 2. The unit ofdisplay 4U comprising a first observing point subpixel 4S and a secondobserving point subpixel 4S and so do the units of display 4U′, 4U″, and4U″′. Here, the first observing point pixel corresponds to a right-eyepixel 4R and the second observing point pixel corresponds to a left-eyepixel 4L. In other words, the unit of display 4U is a pixel forthree-dimensional display of two observing points. Therefore, thedisplay panel 2 is a liquid crystal display panel comprising subpixels4S displaying a left-eye image and subpixels 4S displaying a right-eyeimage for three-dimensional display of two observing points.

The lenticular lens 3 shown in FIGS. 1 and 2 is a lens array comprisinga one-dimensional array of many cylindrical lenses 3 a. A cylindricallens 3 a is a one-dimensional lens having a convex part in a domedshape. The extending direction or longitudinal direction of acylindrical lens 3 a is perpendicular to the arrangement direction of acylindrical lens 3 a in the display plane. The cylindrical lenses 3 ahave no lens effect in the extending direction; they have lens effectonly in the array direction perpendicular to the extending direction.Hence, the lenticular lens 3 is a one-dimensional lens array having lenseffect only in the array direction of the cylindrical lenses 3 a. Thearray direction of the cylindrical lenses 3 a is in accord with thedirection in which the left-eye pixels 4L and right-eye pixels 4R arealternately arranged. The cylindrical lenses 3 a are each positioned inaccordance with the above-mentioned units of display 4U, 4U′, 4U″, and4U″′.

The TFT substrate 2 a of the units of display 4U and 4U′ has the layoutstructure as shown in FIG. 3. The units of display 4U and 4U′ aredifferent in the layout structure because a pixel thin-film transistor4TFT is connected to a gate line G and data line D differently as shownin FIG. 1. Similarly, the units of display 4U″ and 4U″′ are alsodifferent in the layout structure. Here, the units of display 4U, 4U′,4U″, and 4U″′ all comprise a left-eye pixel 4L and a right-eye pixel 4R.Therefore, they are collectively referred to as “a unit of display 4U”for explaining the common structure. Furthermore, in the followingexplanation, the left-eye pixel 4L and right-eye pixel 4R are termed “asubpixel” without distinguishing one from the other for explaining thestructure common to the pixels constituting a unit of display 4U. Inother words, it can be said that a unit of display 4U comprises twosubpixels 4S adjacent to each other. Furthermore, in the followingexplanation, “the display unit” refers to the entire screen region ofthe display panel 2 and “the display region” refers to the aperture of asubpixel 4S for distinction.

Here, as shown in FIG. 3, the optical axes determined according to thestructure of a cylindrical lens 3 a are defined as follows. The convexsurface of a cylindrical lens 3 a facing an user is termed the lensconvex part 31. The trough part between adjacent cylindrical lenses 3 ais termed the lens concave part 32. A virtual line extending along thelongitudinal direction of a cylindrical lens 3 a at the lens convex part31 is termed the first axis 33. A virtual line extending along thelongitudinal direction of a cylindrical lens 3 a at the lens concavepart 32 is termed the second axis 34. The first axis 33 is situated atthe center of a unit of display 4U and the second axis 34 is situated atthe border between adjacent units of display 4U.

As mentioned above, the cylindrical lens 3 a has lens effect only in thedirection perpendicular to its extending direction. Then, in thisembodiment, the direction in which the lens effect appears is in accordwith the direction in which the left-eye pixels 4L and right-eye pixels4R are alternately arranged. Consequently, the cylindrical lens 3 aserves as a light beam separating unit separating light of the left-eyepixel 4L and light of the right-eye pixel 4R into different directions.Then, the lenticular lens 3 can separate an image displayed by theleft-eye pixel 4L and an image displayed by the right-eye pixel 4R intodifferent directions. In other words, the lenticular lens 3 is anoptical member serving as an image separating unit or an imagedistributing unit. Furthermore, having lens effect as mentioned above,the cylindrical lens 3 a has a focal point in accordance with its radiusof curvature. Here, the focal length of a cylindrical lens 3 a isdefined as the distance between the principal point or vertex of thecylindrical lens 3 a and the focal point. The focal length of acylindrical lens 3 a in this embodiment is the distance between thevertex of the cylindrical lens 3 a and the subpixel surface or a surfaceon which the left-eye pixels 4L and right-eye pixels 4R are arranged.The focal length is not confined thereto and can be set as appropriateby changing the radius of curvature or lens position of a cylindricallens 3 a.

In the following explanation, an XYZ Cartesian coordinate system isdefined as follows for the purpose of convenience. In the direction inwhich the left-eye pixels 4L and right-eye pixels 4R are alternatelyarranged, the direction from the right-eye pixel 4R to the left-eyepixel 4L is defined as the +X direction and the opposite direction isdefined as the −X direction. The +X direction and −X direction arecollectively termed the X-axis direction. The longitudinal direction ofa cylindrical lens 3 a is defined as the Y-axis direction. Furthermore,the direction perpendicular both to the X-axis direction and to theY-axis direction is defined as the Z-axis direction. In the Z-axisdirection, the direction from the plane on which the left-eye pixels 4Lor right-eye pixels 4R are arranged to the lenticular lens 3 is definedas the +Z direction and the opposite direction is defined as the −Zdirection. The +Z direction extends forward or to the user. The userviews the display panel 2 on the side facing in the +Z direction.Furthermore, the +Y direction is the direction in which a right-handedcoordinate system is established. In other words, when the thumb of theright hand of a person is pointed in the +X direction and the indexfinger is pointed in the +Y direction, the middle finger points in the+Z direction. In the figures of this specification, the point of originwith a symbol x indicates that the direction from the front to back ofthe sheet is the positive direction and the point of origin with afilled circle indicates that the direction from the back to front of thesheet is the positive direction.

In the following explanation, a line of subpixels arranged in the X-axisis referred to as a row and a line of subpixels arranged in the Y-axisis referred to as a column. Furthermore, when the term “vertical” or“horizontal” is used with respect to the XY-plane, the “vertical”direction is the direction parallel to the Y-axis and the “horizontal”direction is the direction parallel to the X-axis. When the term“upward” or “downward” is used with respect to the XY-plane, the“upward” or “downward” direction is the direction parallel to the Y-axisand the “upward” direction is the +Y direction and the “downward”direction is the −Y direction.

With the XYZ Cartesian coordinate system defined above, the cylindricallenses 3 a are arrayed in the X-axis direction and the left-eye andright-eye images are separated in the X-axis direction. Furthermore, theunits of display 4U comprising left-eye and right-eye pixels 4L and 4Rare lined up in the Y-axis direction. The array pitch of units ofdisplay 4U and the array pitch of cylindrical lenses 3 a in the X-axisdirection are equal. A column of units of display 4U arranged in theY-axis direction is so provided as to correspond to one cylindrical lens3 a.

As shown in FIG. 2, the display pixel 2 has a TFT substrate 2 a and anopposite substrate 2 b with a small space in-between, in which a liquidcrystal layer 5LC is provided. The liquid crystal layer 5LC isconfigured to work, for example, in a transmission TN mode. This is notrestrictive and any other liquid crystal mode can be employed. The TFTsubstrate 2 a is provided on the −Z side of the display panel 2 and theopposite substrate 2 b is provided on the +Z side. Then, the lenticularlens 3 is provided on the +Z side of the opposite substrate 2 b.Polarizing plates 11 are applied to the +Z side of the TFT substrate 2 aand to the −Z side of the opposite substrate 2 b.

The display panel 2 is an active-matrix liquid crystal display panelhaving thin-film transistors (TFTs). The thin-film transistors serve asa switch for transferring display signals to the subpixels. This switchis operated by gate signals running through gate lines connected to thegate of the switch. In this embodiment, data lines D1 to D7 extending inthe column direction (the Y-axis direction) are provided on the surfaceof the TFT substrate 2 a facing the liquid crystal layer 5LC (thesurface facing in the +Z direction). Here, the data lines D1 to D7 arecollectively referred to as the data line D. Furthermore, gate lines G1to G13 extending in the row direction (the X-axis direction) areprovided on the same surface of the TFT substrate 2 a. Here, the gatelines G1 to G13 are collectively referred to as the gate line G. Thedata line D serves to supply display data signals to the thin-filmtransistors.

In this embodiment, the gate lines G extend in the X-axis direction andarrayed in the Y-axis direction. Here, the gate lines G can be angled.When angled, the gate lines G are angled multiple times while extendingin the X-axis direction. On the other hand, the data lines D are angledmultiple times while extending in the Y-axis direction. The data lines Dare arrayed in the X-axis direction. A subpixel 4S (a left-eye pixel 4Lor right-eye pixel 4R) is placed near the intersection between a gateline G and a data line D.

Particularly, in FIG. 1, in order to clarify how a subpixel 4S isconnected to a gate line G and a data line D, for example, a subpixel 4Sconnected to a data line D3 and a gate line G2 is denoted as P32. Inother words, the letter P is followed by the number accompanying thedata line D and then followed by the number accompanying the gate lineG.

In this embodiment, the limited numbers of gate lines G and data lines Dnecessary for explanation are used for easier understanding. However,the numbers are not restricted thereto and do not affect the nature ofthe present invention.

In FIG. 1, in order to clarify how a subpixel 4S is connected to a gateline G and a data line D, the pixel thin-film transistor 4TFT and pixelelectrode 4PIX shown in FIG. 3 are extracted. In FIGS. 3 and 4, thecomponents are shown in different size and scale as appropriate forensuring the visibility of the figure.

As shown in FIG. 1, the region enclosed by adjacent gate lines G anddata lines D forms a pixel region corresponding to a subpixel 4S. Anaperture is formed in such a subpixel 4S.

The display panel 2 has a subpixel structure as shown in FIG. 3 when theTFT substrate 2 a is seen from the observer side. A subpixel 4S isprovided with a data line D, a gate line G, a pixel electrode 4PIX, apixel thin-film transistor 4TFT, a charging capacitor electrode CS2, acharging capacitor line CS, and a silicon layer 4SI. The chargingcapacitor electrode CS2 is formed in the same layer as the chargingcapacitor line CS and electrically connected to the charging capacitorline CS. The charging capacitor 4CS is mainly formed between thecharging capacitor electrode CS2 and an electrode comprising the siliconlayer 4SI via an insulating layer. The charging capacitor electrode CS2is an electrode part corresponding to the region where the chargingcapacitor 4CS is formed. The charging capacitor line CS is a wiremutually connecting the charging capacitor electrodes CS2 of adjacentsubpixels 4S.

The pixel thin-film transistor 4TFT is a MOS thin-film transistor. Oneof the source and drain electrodes is connected to a data line D via acontact hole 4CONT1 and the other is connected to the pixel electrode4PIX via a contact hole 4CONT2. Then, the pixel electrode 4PIX has thesame potential as an electrode comprising the silicon layer 4SI.Consequently, a charging capacitor 4CS is formed between the electrodecomprising the silicon layer 4SI and the charging capacitor electrodeCS2. Then, the gate electrode of the pixel thin-film transistor 4TFT isconnected to a gate line G. Furthermore, an opposite electrode 4COM isformed on the side of the opposite substrate 2 b facing the liquidcrystal layer 5LC. A pixel capacitor 4CLC is formed between the oppositeelectrode 4COM and pixel electrode 4PIX.

In this embodiment, the electrode connected to the pixel electrode 4PIXis termed the source electrode and the electrode connected to a signalline is termed the drain electrode.

Here, as shown in FIG. 3, the contact hole 4CONT1 is shaded in gray, thecontact hole 4CONT2 is filled in black, the pixel electrode 4PIX isindicated by dotted lines, and the silicon layer 4SI is indicated bysolid lines.

As shown in FIG. 1, in this embodiment, one pixel 4P comprises of threeunits of display 4U arranged in the Y-axis direction. Each unit ofdisplay 4 is colored in red, green, or blue as shown in FIG. 13. Red,green, and blue color filters each extend in the X-axis direction andcreate a stripe pattern repeated in the Y-axis direction. The number ofcolors is not limited to three and the monochrome consisting of onecolor can be used. Furthermore, the order of colors is not restricted tothe above and the hue is not restricted to those colors. Three or morecolors can be used. In this embodiment, the color filters and blackmatrix are provided on the surface of the opposite substrate 2 b facingthe liquid crystal layer 5LC.

One pixel 4P comprising three units of display 4U arranged in the Y-axisdirection and has a square shape comprising subpixels 4S arranged inthree rows and two columns. Then, the pixel pitch Pu is presented by3×Py or 2×Px in which Px is the pitch of subpixels 4S in the X-axisdirection and Py is the pitch of subpixels 4S in Y-axis direction, andthe following relationship is satisfied.

Pu=2×Px=3×Py  [Math 1]

The cross-sectional structure at the line D-D′ in FIG. 4 is shown inFIG. 5. The cross-sectional structure at the line R-R′ in FIG. 4 isshown in FIG. 6.

In this specification, the area other than the shielding unit is definedas the aperture. The black matrix 60 in this embodiment is provided tothe opposite substrate 2 b on the side to the liquid crystal layer 5LCas the shielding unit covering all but the apertures of subpixels 4S,and has nearly parallelogram apertures. As shown in FIGS. 5 and 6, theblack matrix 60 covers the pixel thin-film transistor 4TFT, gate line Gand date line D and substantially functions as the shielding unit. Inother words, in this embodiment, the area other than the black matrix 60is the aperture.

In this specification, the term “shielding unit” is used. This is notrestricted to the black matrix 60 in particular and refers to portionsthat transmit no light. Therefore, it is possible that there is no blackmatrix 60 on the date line D or gate line G and the black matrix 60covers only the thin-film transistor TFT and charging capacitorelectrode CS2. In such a case, the date line D or gate line G serves asthe shielding unit.

Here, as mentioned above, the subpixel 4S of the display panel 2 can beconsidered to substantially have a parallelogram shape from its apertureshape; then, the term “parallelogram pixel” is used in the explanation.Of the aperture of a parallelogram pixel, the boundary between the upperedge of the aperture and the shielding unit is defined as the upperside, the boundary between the lower edge of the aperture and theshielding unit is defined as the lower side, and the oblique boundarybetween the right or left edge of the aperture and the shielding unit isdefined as the oblique side. Having a parallelogram shape, the opposingupper and lower sides of a parallelogram pixel are equal in length andthe opposing oblique sides thereof are equal in length. In thisembodiment, the upper and lower sides are larger in length than theoblique sides.

As shown in FIG. 4, the apertures of parallelogram pixels arranged inthe X-axis direction have regions overlapping with each other in theY-axis direction. The shielding unit at the boundary between a right-eyepixel 4R and a left-eye pixel 4L is provided for the purpose ofshielding the wiring part and, therefore, has a width W1 determinedaccording to the width of the wiring part. For efficient placement ofthe wiring part, it is desirable to provide linear wiring parts at theoblique sides of a parallelogram pixel. In such a case, the shieldingwidth is nearly constant.

The lines A-A′, B-B′, and C-C′ are parallel to the Y-axis and situatedin the regions where subpixels 4S adjacent in the X-axis directionoverlap with each other. Particularly, the line A-A′ indicates theboundary between the subpixels 4S adjacent in the X-axis direction in aunit of display 4U. The lines B-B′ and C-C′ indicate the boundarybetween units of display 4U adjacent in the X-axis direction.Furthermore, the line E-E′ is parallel to the X-axis and passes throughthe center Ou of the unit of display 4U. The line F-F′ indicates theboundary between the units of display 4U and 4U′ adjacent to each otherin the Y-axis direction.

Here, the inclination of wires is defined as a positive angle in theclockwise direction with respect to the +Y direction being at 0 degree.The oblique sides in the unit of display 4U have an inclination of +θ1,and the oblique sides in the unit of display 4U′ have an inclination of−θ1. In other words, the wires on the oblique sides of parallelogrampixels are arranged at the same inclination in the X-axis direction andarranged at an inclination +θ1 or −θ1 alternately every other row in theY-axis direction.

Since the aperture of a subpixel 4S is in the shape of a parallelogram,the aperture is equivalent upon rotation by 180 degrees in the XY planeand asymmetric about the line R-R′ or L-L′ parallel to the Y-axis andpassing through the center Or or Ol of the subpixel. Here, the apertureis not restricted in shape to a parallelogram as long as the aperture isequivalent upon rotation by 180 degrees in the XY plane as justmentioned. For example, the aperture can be in any shape including of atrapezoid, polygon, oval, semicircle, crescent, and a shape having acurvature.

The unit of display 4U has the center Ou and the subpixels 4S adjacentto each other in the X-axis direction in the unit of display 4U arepoint-symmetric about the center Ou. The apertures of right-eye andleft-eye pixels 4R and 4L have the centers Or and Ol, respectively,around the intersection of the diagonals of a parallelogram. The centersOr and Ol are shifted in the Y-axis direction to be away from the lineE-E′. The units of display 4U and 4U′ are line-symmetric about the lineF-F′.

There is a region at the boundary between the subpixels 4S (a right-eyepixel 4R and a left-eye pixel 4L) in the unit of display 4U where theirapertures overlap with each other in the Y-axis direction. That regionhas a width X2 in the X-axis direction. On the other hand, there areregions at the boundaries between units of display 4U adjacent to eachother in the X-axis direction where their apertures overlap with eachother in the Y-axis direction. Those regions have a width X3 or X3′ inthe X-axis direction. The subpixels 4S (a right-eye pixel 4R and aleft-eye pixel 4L) of a unit of display 4U have regions where theirapertures do not overlap with each other, namely non-overlappingregions. Those regions have a width X1 in the X-axis direction.

As described above, the subpixels 4S of a unit of display 4U haveparallelogram apertures shifted in the Y-axis direction to be away fromeach other. Therefore, the overlapping width X2 of the apertures ofsubpixels 4S is larger than the overlapping widths X3 and X3′ of theapertures of subpixels 4S between units of display 4U. Then, thefollowing relationship is satisfied for the overlapping regions of theapertures of subpixels 4S.

X2>X3  [Math 2]

X2>X3′  [Math 3]

At the line A-A′, the vertexes of parallelogram apertures adjacent toeach other in the X-axis direction are away from each other in theY-axis direction so as to increase the overlapping width X2 in theX-axis direction and, then, increase the overlapping area. Furthermore,at the lines B-B′ and C-C′, the vertexes of parallelogram aperturesadjacent to each other in the X-axis direction are closer to each otherin the Y-axis direction so as to reduce the overlapping widths X3 andX3′ in the X-axis direction and, then, reduce the overlapping area.

In this specification, the aperture width in the Y-axis direction of theaperture of a subpixel 4S is termed the vertical aperture width.Particularly, the vertical aperture width is the total of the aperturewidths in the Y-axis direction of the apertures of subpixels 4S inregions where the apertures of subpixels 4S (a right-eye pixel 4R and aleft-eye pixel 4L) adjacent to each other in the X-axis directionoverlap with each other in the Y-axis direction.

The vertical aperture width profile in a subpixel of the display panel 2according to this embodiment and the brightness profile of the imagedisplay device 1 are as shown in FIG. 7. As shown in the profile at thetop of FIG. 7, the total width in the Y-axis direction of the aperturesof a left-eye pixel 4L and a right-eye pixel 4R at the line A-A′ islarger than the total widths in the Y-axis direction of the left-eyepixel 4L and right-eye pixel 4R at the lines B-B′ and C-C′. As shown inthe profile at the bottom of FIG. 7, light transmitted through thedisplay panel 2 and lenticular lens 3 is evened and has a gentle profilewhen it is displayed by the image display device 1.

The transistor structure in this embodiment will be described hereafter.

The pixel thin-film transistor 4TFT shown in FIG. 3 is a polysiliconthin-film transistor using polycrystalline silicon as a semiconductor.The polycrystalline silicon is, for example, a P-type semiconductorcontaining a tiny amount of boron. In other words, the pixel thin-filmtransistor 4TFT is a PMOS thin-film transistor that becomes conductivebetween the source and drain electrodes when the gate electrode has apotential lower than the source or drain electrode.

The polysilicon thin-film transistor is formed, for example, by forminga first insulating layer 21 comprising silicon oxide on the TFTsubstrate 2 a, forming an amorphous silicon layer, and polycrystallizingthe amorphous silicon layer to form a polysilicon thin film. Thepolycrystallization can be done by thermal annealing or laser annealing.Particularly, laser annealing using a laser such as an excimer laser canpolycrystallize only the silicon layer while minimizing the temperaturerise in the glass substrate. Therefore, alkali-free glass having a lowmelting point can be used; then, the cost can be reduced. For thatreason, it is called low-temperature polysilicon and widely used. Here,an amorphous silicon thin-film transistor can be realized by eliminatingthe annealing step.

Then, a second insulating layer 22 comprising silicon oxide as a gateinsulating layer is formed on the silicon layer and patterned asappropriate. In this process, it is preferable to dope ions in regionsthat will not be used as the silicon thin-film semiconductor layer so asto make such regions conductive. The patterning can be done by opticalpatterning using a photosensitive resist. For example, a photosensitiveresist is applied by spin-coating, partially irradiated with light usingan exposure device such as a stepper, and developed to leave a film ofphotosensitive resist only in the regions where the pattern will stay.Then, the silicon layer in the regions where the photosensitive resistfilm is absent is eliminated by dry etching or the like. Finally, thephotosensitive resist film is peeled off.

Then, an amorphous silicon layer to form a gate electrode and a tungstensilicide layer are formed so as to create a gate electrode and the like.Here, the gate line to which the gate electrode is connected and/or thecharging capacitor electrode and charging capacitor line can be formedin a similar manner. Then, a third insulating layer 23 comprising asilicon oxide layer and a silicon nitride layer is formed and patternedas appropriate. Subsequently, an aluminum layer and a titanium layer areformed to create a source electrode and a drain electrode. Here, thedata line can concurrently be formed.

Then, a fourth insulating layer 24 comprising silicon nitride is formedand patterned as appropriate. Subsequently, a transparent electrodecomprising, for example, ITO is formed and patterned to create a pixelelectrode 4PIX. Consequently, a subpixel structure having a thin-filmtransistor can be formed. The fourth insulating layer 24 desirably hasflattening effect and can be an insulating layer comprising multipleinorganic and organic films.

Here, the above thin-film transistor can be used to concurrently formthe circuits driving the gate lines, data lines, and charging capacitorlines.

In this embodiment, the gate driver circuit for scanning the gate linesG in sequence is formed on the TFT substrate 2 a concurrently with thethin-film transistors. In this way, the frame of the display panel 2 canbe smaller in width. With the subpixels and gate driver circuit beingformed on the TFT substrate 2 a in an integrated manner, the drivercircuit can have a smaller number of parts, leading to reduced cost andlow power consumption.

An exemplary configuration of the image display device 1 according tothis embodiment and conditions for the lenticular lens 3 to serve as animage distributing unit will be described hereafter. In this embodiment,the image distributing unit has to distribute light emitted from thesubpixels 4S into directions different from each other along the firstdirection in which the left-eye pixels 4L and right-eye pixels 4R arearranged, namely along the X-axis direction. Then, first, the case inwhich the image distributing effect is maximized will be discussed.

As shown in FIG. 8, light emitted from left-eye and right-eye pixels 4Land 4R is distributed by the image separating unit to the left-eye andright-eye observation regions on either side of the line 17 presentingthe center axis of image separation. It is assumed that the distancebetween the principal point, or vertex, of the lenticular lens 3 and thesubpixels is H, the refractive index of the lenticular lens 3 is n, andthe lens pitch is L. Here, the pitch of subpixels 4S intended for anobserving point in the image separation direction is P. In other words,in this embodiment, the pitch Px in the X-axis direction of each of theleft-eye pixels 4L and right-eye pixels 4R is P. The array pitch Pu inthe image separation direction of units of display 4U comprising aleft-eye pixel 4L and a right-eye pixel 4R is 2P.

The distance between the lenticular lens 3 and the observer is referredto as an optimum observation distance OD. The cycle ofenlarged/projected images of subpixels at the distance OD, namely thecycle of widths of projected images of left-eye and right-eye pixels 4Land 4R on a virtual plane at the distance OD from the lens and parallelto the lens, is presented by e. Furthermore, the distance between thecenter of a cylindrical lens 3 a at the center of the lenticular lens 3and the center of a cylindrical lens 3 a at the end of the lenticularlens 3 in the X-axis direction is presented by WL. The distance betweenthe center of a unit of display 4U comprising a left-eye pixel 4L and aright-eye pixel 4R at the center of the display panel 2 and the centerof a unit of display 4U at the end of the display panel 2 in the X-axisdirection is presented by WP. The incident and exit angles of lightto/from a cylindrical lens 3 a at the center of the lenticular lens 3are presented by α and β, respectively. The incident and exit angles oflight to/from a cylindrical lens 3 a at the end of the lenticular lens 3in the X-axis direction are presented by γ and δ, respectively.Furthermore, the difference between the distances WL and WP is C andthere are 2m subpixels in the region over the distance WP.

The array pitch L of cylindrical lenses 3 a and the array pitch P ofsubpixels are related to each other. Therefore, one is determined inconformity to the other. Generally, the lenticular lens is designed inconformity to the display panel. Then, here, the subpixel array pitch Pis treated as a constant. The refractive index n is determined accordingto selection of the material of the lenticular lens 3. On the otherhand, the observation distance OD between the lens and observer and thecycle e of enlarged/projected pixel images at the distance OD are set todesired values. Using these values, the distance H between the lensvertex and subpixels and the lens pitch L are determined. The followingmathematical formulae 4 to 12 are established based on the Snell's lawand geometric relations.

n×sin α=sin β  [Math 4]

OD×tan β=e  [Math 5]

H×tan α=P  [Math 6]

n×sin γ=sin δ  [Math 7]

H×tan γ=C  [Math 8]

OD×tan δ=WL  [Math 9]

WP−WL=C  [Math 10]

WP=Pu×m=2×m×P  [Math 11]

WL=m×L  [Math 12]

Here, the case in which the image distributing effect is maximized isdiscussed. The image distributing effect is maximized when the distanceH between the vertex of the lenticular lens 3 and the subpixels is equalto the focal length f of the lenticular lens 3, which is presented bythe following mathematical formula 13. Assuming that the lens has aradius of curvature r, the radius of curvature r is obtained by thefollowing mathematical formula 14.

f=H  [Math 13]

r=H×(n−1)/n  [Math 14]

The above parameters are summarized as follows. The array pitch P ofsubpixels 4S is determined from the display panel 2. The observationdistance OD and cycle e of enlarged/projected pixel images aredetermined from the settings of the image display device 1. Therefractive index n is determined from the material of the lens. The lensarray pitch L derived from the above and the distance H between the lensand subpixels are parameters for determining the position at which lightfrom the subpixels 4S is projected on the observation plane. Theparameter changing the image distributing effect is the radius ofcurvature r of the lens. In other words, when the distance H between thelens and subpixels 4S is fixed, images from the right and left pixels 4Sare blurred and not clearly separated as the radius of curvature of thelens is deviated from the ideal state. In other words, the range ofradiuses of curvature in which the separation effect is valid should beobtained.

First, the minimum value in the range of radius of curvature in whichthe lens separation effect is valid calculated. As shown in FIG. 9, inorder for the separation effect to be valid, a triangle having a basegiven by the lens pitch L and a height given by the focal length f and atriangle having a base given by the sub pixel pitch P and a height H-fmust be similar. If so, the following mathematical formula 15 issatisfied and the minimum value fmin of the focal length can beobtained.

fmin=H×L/(L+P)  [Math 15]

Next, the radius of curvature is calculated from the focal length. Usingthe mathematical formula 14, the minimum value rmin of the radius ofcurvature can be obtained from the following mathematical formula 16.

rmin=H×L×(n−1)/(L+P)/n  [Math 16]

Next, the maximum value is calculated. As shown in FIG. 10, in order forthe separation effect to be valid, a triangle having a base given by thelens pitch L and a height given by the focal length f and a trianglehaving a base given by the subpixel pitch P and a height f−H must besimilar.

Then, the following mathematical formula 17 is satisfied and the maximumvalue fmax of the focal length can be obtained.

fmax=H×L/(L−P)  [Math 17]

Next, the radius of curvature is calculated from the focal length. Usingthe mathematical formula 14, the maximum value rmax of the radius ofcurvature can be obtained from the following mathematical formula 18.

rmax=H×L×(n−1)/(L−P)/n  [Math 18]

In summary, in order for a lens to have the image distributing effect,the lens has to have a radius of curvature in the range given by thefollowing mathematical formula 19 presented by the mathematical formulae13 and 15.

H×L×(n−1)/(L+P)/n≦r≦H×L×(n−1)/(L−P)/n  [Math 19]

In the above explanation, an image display device of two observingpoints having left-eye pixels 4L and right-eye pixels 4R is described.This embodiment is not restricted thereto. For example, this embodimentis similarly applicable to an image display device of N observingpoints. In other words, in the N observing point scheme, the pitch Pu ofunits of display 4U and the pitch P of subpixels have the relationshipPu=N×P. In such a case, N×m subpixels are included in the region overthe above-described distance WP instead of 2m subpixels.

In the configuration of this embodiment, it is difficult to fullycontrol the vertical aperture ratio near the vertexes of the obliquesides of a parallelogram aperture due to the accuracy of processing theshielding unit. Then, in this embodiment, as shown in FIGS. 9 and 10,the focal point of the lens is shifted from the subpixel surface to bluran image, thereby reducing influence of the accuracy of processing theshielding unit and improving the image quality.

The technique of shifting the focal point of the lens from the subpixelsurface to establish a blurred region as described above for higherimage quality will be termed “the defocusing effect” in the followingexplanation. Furthermore, the width of an effective region in which theblurring occurs is termed “the spot diameter.” In this embodiment, thewidth over which effective blurring occurs in the X-axis direction isthe spot diameter SP. The spot diameter SP is determined in accordancewith the distance from the focal point of the lens and, therefore, canbe set by adjusting the thickness of the lenticular lens sheet and/orpolarizing plate 11 of the opposite substrate 2 b.

Here, the width of an oblique side in the X-axis direction, WX1, isgiven by WX1=W1/sin θ1 as seen in FIG. 4. The distance between thevertexes of an oblique side of a parallelogram aperture is 2×X2. Here,it is preferable that the spot diameter SP on the subpixel surface whenthe focal point of the lens is shifted from the subpixel surface isbetween WX1 and 2×X2. When the spot diameter is equal to WX1, this isthe borderline diameter to blend and blur the oblique side area of aparallelogram aperture; it is preferable that the spot diameter SP islarger than this. When the spot diameter is equal to 2×X2, the blurredregion can be extended to the intersection between the oblique side andupper base of a parallelogram aperture and to the intersection betweenthe oblique side and lower base. However, if the blurred region isfurther extended, the separation performance of the lens deteriorates.Hence, for giving priority to the separation performance in designing alens, it is preferable that the radius of curvature of the lens iswithin the range satisfying the following mathematical formula 20 or 21.

H×L×(n−1)/(L+2×X2)/n≦r≦H×L×(n−1)/(L+WX1)/n  [Math 20]

H×L×(n−1)/(L−WX1)/n≦r≦H×L×(n−1)/(L−2×X2)/n  [Math 21]

Furthermore, in this embodiment, the width of an oblique chargingcapacitor line CS in the X-axis direction, WX2, is given by WX2=W2/sinθ1 as seen in FIG. 4. For blending and blurring the intersection betweena charging capacitor line CS and the oblique side of a parallelogramaperture, the spot diameter SP is preferably between WX1 and 2×(WX2+X2).When the spot diameter is equal to WX1, this is the borderline diameterto blend and blur the oblique side area of a parallelogram aperture; itis preferable that the spot diameter SP is larger than this. This isparticularly effective when the accuracy of processing the chargingcapacitor line CS largely impacts the image quality. However, if theblurring rate is further increased, the magnitude of 3D crosstalk isunfavorably increased. Hence, it is preferable that the radius ofcurvature of the lens is within the range satisfying the followingmathematical formula 22 or 23.

H×L×(n−1)/(L+2×WX2+2×X2)/n≦r≦H×L×(n−1)/(L+WX1)/n  [Math 22]

H×L×(n−1)/(L−WX1)/n≦r≦H×L×(n−1)/(L−2×WX2−2×X2)/n  [Math 23]

As described above, the spot diameter SP can be adjusted by changing thedistance between the subpixels and lens for obtaining the defocusingeffect. However, with any technique being used to produce the lenticularlens 3 among molding using a die, photolithography, inkjet, and so on, agiven shape is ensured more at the lens convex part 31 of a cylindricallens 3 a than at the lens concave part 32 between adjacent cylindricallenses 3 a. The lens convex part 31 tends to have higher opticalperformance. It is more difficult to remove unpeeled residues and/oradherent foreign substances from the lens concave part 32 than from thelens convex part 31. This causes the lens concave part 32 to have loweroptical separation performance. Therefore, there will be difference inthe spot diameter SP between the lens convex part and concave part of alenticular lens, which causes an unevenly profiled defocusing effect inone and the same plane.

As shown in FIG. 7, when the image separating unit has a spot diameterSP2 larger than a spot diameter SP1, the larger spot diameter SP2 isapplied to the region where the vertical aperture width fluctuates more,whereby fluctuation in the brightness, namely 3D moire, can effectivelybe reduced. Furthermore, in the region to which the smaller spotdiameter SP1 is applied, 3D crosstalk can effectively be reduced. Then,high quality three-dimensional display having 3D moire and 3D crosstalkbalanced can be obtained. The spot diameter SP1 at the lens convex part31 and the spot diameter SP2 at the lens concave part 32 have thefollowing relationship.

SP1<SP2  [Math 24]

The subpixel structure in this embodiment will be described in detailhereafter. In order to achieve a high aperture ratio and high imagequality in a display device for multiple observing points, the verticalaperture ratio should be maximized while the vertical aperture ratio insubpixels adjacent to each other at the center of a unit of display 4Uis made nearly constant regardless of the position in the horizontaldirection. Here, the vertical aperture ratio is a value obtained bydividing the width in the Y-axis direction of the aperture in across-section of a subpixel at a line extending in the directionperpendicular to the image separation direction (the X-axis direction inthis embodiment) of the image separating unit (namely, extending in theY-axis direction) by the subpixel pitch in the Y-axis direction. Such avertical aperture ratio should be maximized while being made nearlyconstant in the image separation direction.

First, it is preferable that the gate line G and data line D areprovided around each subpixel. In this way, the dead space between wiresis reduced and the aperture ratio is improved. In other words, it is notrecommended to provide the gate lines G or data lines D themselves nextto each other with no subpixel in-between. This is because the wires ofthe same kind have to be spaced to prevent short-circuit when they areprovided next to each other. Such a space will become a dead space andreduce the aperture ratio.

The shielding layer and color filters can be provided to the TFTsubstrate 2 a. In this way, the accuracy of superimposition can beimproved, allowing the shielding layer to have a smaller width so as toincrease the aperture ratio. On the other hand, reducing the width ofthe shielding layer covering the gate line G leads to reduction in 3Dmoire, improving the display quality.

The subpixel structure and lens effect in this embodiment will bedescribed in detail hereafter.

First, the definition of 3D moire in this specification is discussed.The image display device 1 according to this embodiment has theluminance profile as shown in FIG. 11. Here, the observation position Xon the abscissa presents the angle indicating the image separationdirection. The direction perpendicular to the display surface, namelythe +Z-axis direction, is at 0 degree. The brightness Y on the ordinatepresents relative luminance with respect to the luminance of 100 in the+Z-axis direction in the luminance profile associated with the angulardirection. A line Y (LWRW) presents the profile of luminance when bothsubpixels, a left-eye pixel 4L and a right-eye pixel 4R, display white.A line Y (LBRB) presents the profile of luminance when both subpixels, aleft-eye pixel 4L and a right-eye pixel 4R, display black. A line Y(LWRB) presents the profile of luminance when a left-eye pixel 4Ldisplays white and a right-eye pixel 4R displays black. A line Y (LBRW)presents the profile of luminance when a left-eye pixel 4L displaysblack and a right-eye pixel 4R displays white.

The profile of luminance at the observer position on the +X sidecorresponds to an image output to the right eye. The profile ofluminance at the observer position on the −X side corresponds to animage output to the left eye. The dotted lines present the profile ofluminance when only one subpixel, a right-eye pixel 4R or a left-eyepixel 4L, outputs an image. The solid line presents the profile ofluminance when both subpixels display an image. Therefore, the total ofthe profiles of luminance at the observing points presented by thedotted lines is equal to the profile of luminance presented by the solidline.

In order to address the problem with the above-described optical unit,the lens concave part 32 having low optical separation performance isprovided in the regions near the lines B-B′ and C-C′ where the verticalaperture width largely fluctuates. In this way, a high level ofdefocusing effect occurs at the lens concave part 32, thereby blurringlight emitted from the pixels and flattening the profile of luminance.Consequently, 3D moire can be reduced to a subjectively acceptablelevel. Furthermore, in the regions near the lines B-B′ and C-C′ wherethe vertical aperture width largely fluctuates, the overlapping regionshave smaller widths X3 and X3′, whereby the blurring as a result of thedefocusing effect does not result in increasing 3D crosstalk. On theother hand, the lens convex part 31 having high optical separationperformance is provided in the region near the line A-A′ where thevertical aperture width slightly fluctuates so as to efficientlydistribute light and reduce 3D crosstalk. Then, the display panel 2 ofthis embodiment can control 3D moire and 3D crosstalk in accordance withthe profile of optical separation performance of the image separatingunit, providing high quality three-dimensional images.

Furthermore, as shown in FIG. 16, the image display device 1 is oftenplaced in the manner that the observer views the display surfacesquarely. Therefore, the image quality in front of the display surfaceis important. In this embodiment, with the lens convex part 31 havinghigh optical separation performance being provided at the line A-A′, thedefocusing is reduced to achieve efficient image separation in front.Then, light loss can be reduced and the luminance in front can beimproved.

The subpixel according to this embodiment has a nearly constant verticalaperture ratio in the image separation direction at the center of a unitof display 4U. However, the vertical aperture ratio may not becompletely constant because of the processing accuracy in the course ofproducing the TFT and/or panel; the luminance may fluctuate depending onthe observer position X. Particularly, when the TFT substrate 2 a andopposite substrate 2 b are largely misaligned in the Y-axis direction,the luminance tends to fluctuate under the influence of the black matrix60 shielding the gate line G. As shown in FIG. 11, the luminancefluctuation near a point (X0, Y0) is caused by the shielding unitcrossing the line A-A′ and the luminance fluctuation near points (XR5,YR5) and (XL5, YL5) is caused by the shielding unit crossing the lineB-B′ or line C-C′. Such luminance fluctuation is called 3D moire. The 3Dmoire associated with the lines A-A′, B-B′, and C-C′ is presented byΔYC, ΔYL, and ΔYR, respectively. In this embodiment, they are defined asfollows.

YC=(YL1+YR1)/2  [Math 25]

ΔYC=(YC−Y0)/YC

ΔYL=(YL1−YL5)/YL1

ΔYR=(YR1−YR5)/YR1  [Math 26]

ΔYC/ΔXC=ΔYC/( XR1−XL1)/2

ΔYL/ΔXL=ΔYL/( XL1−XL5)

ΔYR/ΔXR=ΔYR/( XR5−XR1)  [Math 27]

Furthermore, the viewable ranges eR and eL of the right and left eyesare defined as follows.

eR=|XR2−X1|  [Math 28]

eL=|X1−XL2|  [Math 29]

The calculation using the above mathematical formulae revealed that the3D moire ΔYC, ΔYL, and ΔYR were 20%, 27%, and 25%, respectively. Asshown in FIG. 7, the total vertical aperture widths at the lines B-B′and C-C′ are smaller than the total vertical aperture width at the lineA-A′. The fluctuation in width with respect to the aperture width Y1 inFIG. 7 is ΔH2 at the line A-A′ and ΔH1 at the lines B-B′ and C-C′. Thefluctuation in width ΔH1 is four times larger than the fluctuation inwidth ΔH2. The total vertical aperture widths at the lines B-B′ and C-C′abruptly fluctuate. However, since the spot diameter SP2 at the lensconcave part is larger than the spot diameter SP1 at the lens concavepart, the fluctuation in luminance corresponding to the lines B-B′ andC-C′ is flattened and the difference in 3D moire among ΔYC, ΔYL, and ΔYRis reduced in the luminance profile shown in FIG. 11.

The inventors of the present invention found in subjective assessmentresults that the display quality can be maintained without giving theobserver discomfort where the luminance fluctuation is within 30%.Therefore, the above 3D moire ΔYC, ΔYL, and ΔYR is all within thesubjectively acceptable range. Furthermore, it is desirable that thefluctuation in vertical aperture ratio at the line A-A′ in FIG. 4 isdesigned to be within 30%. To this end, the following relationship mustbe satisfied.

0.7<(Y1−W1/sin θ1)/Y1<1.3  [Math 30]

Furthermore, even if the fluctuation in vertical aperture ratio in theimage separation direction is 30% or higher in a subpixel layout, thedefocusing effect can be utilized to equalize the light transmittedthrough the region where the vertical aperture largely fluctuates toreduce the 3D moire to approximately 15%, or a half. Since therestrictions on the design can be alleviated by utilizing the defocusingeffect, the fluctuation in vertical aperture ratio can be designed to bewithin 60% in consideration of the defocusing effect.

Furthermore, the 3D crosstalk is the mixture ratio of an image for oneobserving point to an image for the other observing point as describedabove. The minimum value L_CTmin of 3D crosstalk in the left-eyeviewable range eL and minimum value R_CTmin of 3D crosstalk in theright-eye viewable range eR are defined as follows.

L _(—) CTmin=(YL3−YL4)/(YL6−YL4)

R _(—) CTmin=(YR3−YR4)/(YR6−YR4)  [Math 31]

If the 3D crosstalk minimum values L_CTmin and R_CTmin are equal to orlower than a given value, the observer can enjoy excellentthree-dimensional visibility. Subjective assessment results revealedthat the 3D crosstalk minimum values L_CTmin and R_CTmin in the left-eyeand right-eye viewable ranges eL and eR are desirably equal to or lowerthan 5 to 10%.

Therefore, the range providing excellent three-dimensional observationcan be increased as the range of observation position in the X-axisdirection in which 3D crosstalk is equal to or lower than 5 to 10% isextended. Here, the range of observation position in the X-axisdirection in which 3D crosstalk is equal to or lower than a given valueis defined as follows. As shown in FIG. 11, the range proving excellentthree-dimensional visibility in the left-eye viewable range eL isdefined as CT_Lx and the range proving excellent three-dimensionalvisibility in the right-eye viewable range eR is defined as CT_Rx.

In this embodiment, the range of observation position in the X-axisdirection in which 3D crosstalk is equal to or lower than 7.5% wasassessed. The range of 3D crosstalk allowing for excellentthree-dimensional visibility can be assessed using an optical measuringdevice having the angular resolution and determined in combination withsubjective assessment. However, the absolute quantity of assessment mayvary depending on the design specification of an optical measuringdevice. For that reason, the range of observation position in the X-axisdirection is not restricted to the range in which 3D crosstalk is equalto or lower than 7.5%, and can be determined as appropriate based on themeasuring results from an optical measuring device and subjectiveassessment results.

As a result of assessment using the same lenticular lens 3 in the pixelstructures described in the Patent Literature 1 and Patent Literature 2in which the vertical aperture width is constant in the image separationdirection, the 3D moire between (XL1, YL1) and (XL5, YL5) and between(XR1, YR1) and (XR5, YR5) was excellent. However, the 3D crosstalkbetween (XL1, YL1) and (XL5, YL5) and between (XR1, YR1) and (XR5, YR5)was larger than the 3D crosstalk between (XL1, YL1) and (X0, Y0) andbetween (XR1, YR1) and (X0, Y0). Particularly, the 3D crosstalk between(XL1, YL1) and (XL5, YL5) and between (XR1, YR1) and (XR5, YR5) wasequal to or higher than 7.5% and the ranges CT_Lx and CT_Rx werediminished toward the point of origin. Consequently, thethree-dimensional viewable range was narrowed and the three-dimensionaldisplay performance was deteriorated.

With the units of display 4U being placed in accordance with the opticalseparation performance profile of the lenticular lens 3 serving as theimage separating unit, the image display device 1 according to thisembodiment can reduce 3D crosstalk to increase the region providingexcellent three-dimensional visibility while reducing 3D moire to withina subjectively acceptable range. Furthermore, at the center of a unit ofdisplay 4U, light is efficiently distributed by the lens effect of highoptical separation performance, whereby the luminance in front of thedisplay region can be improved.

The drive method, or display operation, of the display panel accordingto this embodiment having the above configuration will be describedhereafter.

In this embodiment, the display panel 2 is driven by dot inversiondrive. In the dot inversion drive, as shown in FIG. 12, the polarity ofdisplay data to be transferred is inverted with respect to a referencepotential every data line, every gate line, and every frame. The dotinversion drive is also called the 1H1V inversion drive. This is becausethe polarity is inverted every data line arrayed in the horizontaldirection (H direction) and every gate line arrayed in the verticaldirection (V direction).

As shown in FIG. 13, signals of the same sign polarity are written inthe subpixels of which the upper and lower sides of parallelogram pixelsare adjacent to each other in the vertical direction. With the regionswhere the upper and lower sides of parallelogram pixels adjacent to eachother having the same polarity, defective orientation and/ordisclination of the liquid crystal molecules along the gate line Gextending in the X-axis direction is prevented. Then, light leakage isreduced and high contrast is obtained. Furthermore, the black matrix 60provided around the gate line G for preventing deterioration in thecontrast due to light leakage can have a smaller width W2, increasingthe aperture ratio.

This embodiment can reduce fluctuation in the potential of the chargingcapacitor line CS and charging capacitor electrode CS2 in the subpixelsupon writing display data in the subpixels. This will be discussedhereafter. Attention is paid to two units of display 4U adjacent to eachother in the X-axis direction in FIG. 13. Among the subpixels 4S inthese units of display 4U, different polarities are written in thesubpixels 4S selected by the common gate line G in the same gateselection period. Then, as shown in FIG. 3, the charging capacitor lineCS is electrically connected to the charging capacitor electrode CS2between the subpixels 4S adjacent to each other in the X-axis directionso that the charging capacitor electrodes CS2 of the subpixels 4Sadjacent to each other in the X-axis direction have the same potential.Consequently, the potential of the charging capacitor electrode CS2 doesnot shift to one polarity in the subpixels 4S of which the gate periodis selected concurrently. Then, the crosstalk occurring in the directionin which the charging capacitor line CS and charging capacitor electrodeCS2 extend can be reduced and high quality display can be realized.

Furthermore, not only display data of the positive polarity but alsodisplay data of the negative polarity are written in the subpixels 4S intwo consecutive gate selection periods. Consequently, the configurationof this embodiment has the effect of reducing fluctuation in thepotential of the charging capacitor line CS in using conventional dotinversion drive and allows the subpixels 4S of which the upper and lowersides of parallelogram apertures are adjacent to each other in thevertical direction to have the same polarity. In this way, high imagequality display can be realized at a low cost.

Here, the reference potential for dot inversion drive can be thepotential of the common electrode facing the pixel electrode 4PIX.However, precisely speaking, the common electrode potential is often aDC offset applied for reducing influence of feed-through of the pixelthin-film transistor 4TFT and is different from the reference potential.

The display panel 2 is placed with the long side oriented in the X-axisdirection and the short side oriented in the Y-axis direction as shownin FIG. 14. Having the image separation direction in accord with theX-axis direction, the display panel 2 is a display panel accommodatinglandscape (wide-screen) display. A drive IC 7 for controlling videosignals is mounted on a long side of the TFT substrate 2 a of thedisplay panel 2. The output of the drive IC 7 is connected to the datalines of the display unit 6. Generally, the output pin pitch of thedrive IC 7 is smaller than the data line pitch. Therefore, the wiresextending from the output pins of the drive IC 7 to the data lines mustbe spread and, therefore, some distance is necessary between the driveIC 7 and display unit 6. Furthermore, a multiplexer circuit for datasignals can be installed in the drive IC 7 and a switching circuitcapable of sorting data signals output from the drive IC 7 in atime-sharing manner according to the operation of the multiplexercircuit can be provided on the TFT substrate 2 a. In this way, thenumber of data signal wires output from the drive IC 7 to be connectedcan be reduced.

Furthermore, in this embodiment, the gate driver circuit for scanningthe gate lines in sequence is formed on the TFT substrate 2 aconcurrently with the thin-film transistors. In this way, the framewidth of the display panel 2 at the long side can be reduced.Furthermore, the display panel 2 can have a smaller frame on each sideby providing the drive IC 7 connected at a long side of the displaypanel 2 on a long side and integrating the gate driver circuit connectedat a short side of the display panel 2. The display panel 2 havingsmaller frames is smaller in size and the number of display panels 2obtained from one mother board is increased, thereby reducing the cost.Furthermore, integral formation of the subpixels and gate driver circuiton the TFT substrate 2 a leads to reduction in the number of parts ofthe driver circuit, thereby reducing the cost and power consumption.

The image display device 1 as described above has the subpixels 4S inwhich the data line D, gate line G, charging capacitor electrode CS2,and switching unit are efficiently placed, ensuring highthree-dimensional image quality while improving the aperture ratio.

Furthermore, in the subpixel structure of the display panel 2, thevertical aperture width at the lines B-B′ and C-C′ is different from thevertical aperture width at the line A-A′. The optical unit has theoptical separation performance profile in accordance with the aperturewidth. Therefore, light output from the display panel 2 can efficientlybe distributed by the optical unit, improving the three-dimensionalimage display quality.

The display panel 2 mounted on the image display device 1 comprisessquare pixels 4P in which the subpixels 4S for two observing points (aright-eye pixel 4R and a left-eye pixel 4L) are arranged in the imageseparation direction. Therefore, the two-dimensional display (2Ddisplay) is provided when the right-eye pixel 4R and left-eye pixel 4Ldisplay the same image and the three-dimensional display (3D display) isprovided when the right-eye pixel 4R and left-eye pixel 4L displaydifferent images. The subpixels 4S can be driven independently. Then,the three-dimensional display (3D display) and two-dimensional display(2D display) can be mixed on the same screen.

Furthermore, the image display device 1 according to this embodiment canbe installed in a cellular phone 9 as shown in FIGS. 15A to 15C. Asshown in FIG. 15A, the X-axis direction of the image display device 1 isin accord with the lengthwise direction of the screen of the cellularphone 9 and the Y-axis direction of the image display device 1 is inaccord with the crosswise direction of the screen of the cellular phone9. Then, as shown in FIGS. 15B and 15C, the screen part of the cellularphone 9 is provided with a hinge having a rotation shaft so that thescreen part is movable. Then, the display screen can be orienteddifferently according to the usage environment so that the imageseparation direction, namely the X-axis direction, is nearly parallel tothe line connecting the eyes of the viewer for use. Consequently, theobserver can easily view the three-dimensional display. Furthermore, thedisplay panel 2 in this embodiment has a narrow frame and, therefore, isfavorably applicable to portable devices without imposing any limitationon the functionality, design, and operability required for portabledevices.

In this embodiment, the subpixel on the +X side of a unit of display 4Uis a left-eye pixel 4L and the subpixel on the −X side of the unit ofdisplay is a right-eye pixel 4R. However, this is not restrictive. Thefirst observing point pixel and second observing point pixels can be aright-eye pixel 4R and a left-eye pixel 4L, respectively. In this way,after the display panel 2 is rotated in the XY plane by 180 degrees, thesame three-dimensional display can be provided by rearranging the imagedata. Particularly, provided with a rotatable display screen, theportable device as shown in FIG. 15 is highly operable. Informationshould be provided regardless of how the image display device 1 isoriented in the hands of the observer. Therefore, the image displaydevice 1 according to this embodiment is effectively applicable to suchportable devices.

MODIFIED EMBODIMENT OF EMBODIMENT 1

In this embodiment, the source and drain electrodes of a pixel thin-filmtransistor 4TFT become conductive when the gate electrode has apotential lower than the source or drain electrode. Conversely, aso-called NMOS thin-film transistor that becomes conductive when thegate electrode has a potential higher than the source or drain electrodecan be used.

Furthermore, in this embodiment, the contact holes 4CONT1 and 4CONT2 ofa subpixel 4S are shifted from the center of the subpixel in the X-axisdirection. The observing point of the observer is highly possiblysituated near the vicinity of the center of a subpixel 4S that isenlarge and projected on the observation plane by the image separatingunit such as a lens. The contact holes 4CONT1 and 4CONT2 provided nearthe center of a subpixel 4S may disturb the orientation of liquidcrystal molecules and adversely impact the display. Therefore, if thecontact holes 4CONT1 and 4CONT2 are provided near the center of asubpixel 4S, the most viewed part is more likely to be subject todeterioration in the image quality. Then, as in this embodiment, thecontact holes 4CONT1 and 4CONT2 shifted from the vicinity of the centerof a subpixel contribute to improving the display image quality.

Furthermore, in this embodiment, as for the position of the pixelthin-film transistors 4TFT in the subpixels 4S of which the upper andlower sides of parallelograms are adjacent to each other in the verticaldirection, the pixel thin-film transistors 4TFT of the subpixels 4S arepositioned in an asymmetric manner in the X-axis direction with respectto the center line of the subpixels 4S. Consequently, the pixelthin-film transistors 4TFT of subpixels can be positioned in diversemanners in the subpixels 4S so that influence of multiple pixelthin-film transistors 4TFT does not overlap with each other at the sameposition on the observation plane, allowing for high image quality.

Furthermore, in this embodiment, the black matrix 60 as the shieldinglayer in the opposite substrate 2 b is larger than the line width of thesubpixels 4S on the TFT substrate 2 a in consideration of misalignmentbetween the opposite substrate 2 b and TFT substrate 2 a. In otherwords, in the above explanation, the shielding layer covering all butthe apertures of subpixels can be formed by the wiring on the TFTsubstrate 2 a. Such a shielding layer may cover at least a part of theaperture of a subpixel 4S, and the aperture formed by the shieldinglayer and the aperture of a subpixel 4S may be similar. Furthermore, theaperture formed by the shielding layer may be smaller than the apertureof a subpixel 4S. In this way, even if the TFT substrate 2 a andopposite substrate 2 b are misaligned, the aperture shape is subject toless change, allowing for high image quality.

The connection between a gate line G/a data line D and a subpixel 4S inthis embodiment can also be described as follows. A column of subpixels4S between any two of multiple data lines D may include subpixels 4Sconnected to one data line D via a pixel switch and subpixels 4Sconnected to the other data line D via a pixel switch in an alternatemanner. Furthermore, a row of subpixels 4S between any two of multiplegate lines G may include subpixels 4S connected to one gate line G via apixel switch and subpixels 4S connected to the other gate line G via apixel switch in an alternate manner. For the above arrangement, it ispreferable that the number of data lines D is larger than the number ofcolumn of subpixels 4S by one. Similarly, it is preferable that thenumber of gate lines G is larger than the number of rows of subpixels 4Sby one.

In this embodiment, the lenticular lens 3 has the lens surface on theside facing in the +Z direction, namely facing the user. However, thisis not restrictive. The lens surface may be provided on the side in the−Z direction, namely facing the display panel 2. In such a case, thedistance between the lens and subpixels can be reduced, which isadvantageous for accommodating higher resolutions.

Furthermore, the unit of display 4U can be in the shape of a square. Theshape of a square means that the pitch in the X-axis direction of unitsof display 4U for N observing points, Pu=N×Px, is equal to the pitch inthe Y-axis direction thereof, Py, and the relationship Pu=N×Px=Py issatisfied. In other words, the pitch of units of display 4U is equal inall directions in which the units of display are repeatedly arranged.

In the above explanation, multiple observing points are set on theobservation plane and the subpixels for those observing points of allunits of display 4U on the display surface emit light for the setobserving points. This scheme collects light for set observing points atthe corresponding observing points, and is also called the lightcollection scheme. The above-described three-dimensional display deviceof two observing points and three-dimensional display devices ofmultiple observing points in which the number of observing points isfurther increased are classified as the light collection scheme. Theconcept of the light collection scheme can be presented as shown in FIG.16. As shown in FIG. 16, the lines 17 presenting the center axis ofimage separation gather at the observing points of the observer and theobserver can observe independent images with the right and left eyes.The light collection scheme is characterized in that light beamsentering the eyes of the observer are reproduced for display. The imagedisplay device 1 according to this embodiment is effectively applicableto the light collection scheme.

Furthermore, as shown in FIG. 16, the direction of light emitted fromthe cylindrical lenses 3 a of the lenticular lens 3 is set according tothe viewing position of the observer. The lines 17 presenting the centeraxis of image separation are oriented to the observer. The right-eye andleft-eye images are distributed to the left eye 55L and right eye 55R,respectively, with respect to the center axis of image separation. Thecylindrical lenses 3 a have a convex, curved surface, of which thehighest point in the Z axis direction is the vertex. A virtual lineextending through the vertex of the lens convex part 31 in thelongitudinal direction of a cylindrical lens 3 a can form a first axis33 when the pitch of cylindrical lenses 3 a and the pitch of units ofdisplay 4U are equal. However, since the pitch L of the cylindricallenses 3 a is different from the pitch Pu of the units of display 4U inthis embodiment when the cylindrical lenses 3 a and units of display 4Uare seen in the direction perpendicular to the display surface, thevertex of a cylindrical lens 3 a does not always coincide with thecenter line A-A′ of a unit of display 4U. This is because the lines 17presenting the center axis of image separation gather at one point onthe observer and the center axis of image separation seen from theobserver serves as an apparent optical axis. In this specification, thecenter axis of image separation seen from the position of the observeris defined as the first optical axis 33. As shown in FIG. 16, the line17 presenting the axis of image separation is perpendicular to thedisplay surface and the first optical axis 33 for observation in thedirection perpendicular to the display surface coincides with the lineA-A′ at the center of the display unit of the display panel 2.

Furthermore, schemes called spatial image, spatial image reproduction,spatial image reconstruction, and spatial image formation schemes havebeen proposed. The concept of these schemes can be presented as shown inFIG. 17. Unlike the light collection scheme, the spatial image schemehas no specific observing point. The spatial image scheme is differentfrom the light collection scheme in that light emitted from an object inthe space is reproduced to display the object. Three-dimensional imagedisplay devices of integral photography, integral videography, andintegral imaging schemes are classified as the spatial image scheme. Inthe spatial image scheme, the observer at an arbitrary position does notview only the subpixels for the same observing point throughout thedisplay surface. However, there are multiple kinds of regions having agiven width and formed by the subpixels for the same observing point. Ineach region, the image display device 1 according to this embodiment canyield the same effect as in the light collection scheme. Therefore, theimage display device 1 according to this embodiment can also effectivelyapplicable to the spatial image scheme.

In this embodiment, the term “observing point” refers to “the positionfrom which the image display device is viewed (observation position)” or“a point or a region at which or in which the eye of the user should bepositioned,” not to “the point on the display region to which the userpays attention (viewing point).”

The polarizing plate 11 can be applied to a side of the lenticular lens3 instead of being applied to the display panel 2 installed in the imagedisplay device 1 according to this embodiment. Furthermore, thepolarizing plate 11 can be provided on the observer's side of thelenticular lens 3. With the polarizing plate 11 positioned differently,the distance H between the vertex of the lens and the subpixels can beadjusted in a simple manner. Consequently, the freedom of design can beimproved. Furthermore, the image separating unit installed in the imagedisplay device 1 according to this embodiment is not restricted to thelenticular lens 3 and can be those using a parallax barrier comprisingalternate transparent and nontransparent regions. The parallax barriercan be an electro-optical element in which the transparent andnontransparent regions are switched by liquid crystal molecules or aMEMS shutter. Furthermore, the effects of this embodiment can beobtained by using a GRIN (gradient index) lens, which is anelectro-optical element using liquid crystal, as the image separatingunit.

The liquid crystal display panel of the image display device 1 of thisembodiment is not restricted to those of the TN liquid crystal drivemode, and can be those of other liquid crystal drive modes. Examples ofthe liquid crystal drive mode include IPS (in-plain switching), FFS(fringe field switching), and AFFS (advanced fringe field switching)modes among horizontal electric field modes, and MVA (multi-domainvertical alignment) employing multiple domains to diminish the viewingangle dependency, PVA (patterned vertical alignment), and ASV (advancedsuper v) modes among vertical orientation modes. Furthermore, the liquidcrystal display panels of OCB (optically compensated bend) and filmcompensation TN modes can appropriately be used.

Furthermore, in the above explanation, the display panel 2 according tothis embodiment is a liquid crystal display panel utilizing liquidcrystal molecules as the electro-optic element. The display panel 2 isapplicable not only to a transmissive liquid crystal display panel, butalso to a reflective liquid crystal display panel, semitransmissiveliquid crystal display panel, slightly reflective liquid crystal displaypanel including the transmission region at a higher ratio than thereflective region, and slightly transmissive liquid crystal displaypanel including the reflective region at a higher ratio than thetransmission region. Furthermore, the drive method of the display panel2 is favorably applicable to the TFT scheme. The thin-film transistorsin the TFT scheme are favorably applicable not only to those ofamorphous silicon, low-temperature polysilicon, high-temperaturepolysilicon, and monocrystalline silicon, but also to those of organicmaterials such as pentacene, metal oxides such as zinc oxide, and carbonnanotubes. Furthermore, the display panel 2 according to this embodimentdoes not rely on the structure of thin-film transistors and those ofbottom-gate, top-gate, staggered, and inversely-staggered types canfavorably be used.

In this embodiment, the subpixels have a pixel thin-film transistor 4TFTwith a double gate. However, this is not restrictive and the pixelthin-film transistor 4TFT may have a single or triple gate structure.The multi-gate structure such as double and triple gates serves toreduce optical leak current when the thin-film transistor is off,preventing the TFT properties from deteriorating due to light from thebacklight or from outside the image display device. Consequently,flickers, noise, and crosstalk can be reduced and a high quality imagedisplay device can be provided. Particularly, polysilicon thin-filmtransistors have low resistance between the source and drain comparedwith amorphous thin-film transistors and, therefore, the abovemulti-gate structure can be very effective. Furthermore, the multi-gatestructure is effective for increasing the luminance of the backlight togain the brightness in the case of highly fine pixels.

Furthermore, the display panel 2 is applicable to a display panel thatis not of a liquid crystal type such as an organic electroluminescencedisplay panel, or a PALC (plasma address liquid crystal). In an organicelectroluminescence display panel, the non-light emitting region servesas the light blocking region. Application of the structure of theshielding unit of this embodiment to the non-light emitting region canlead to the same effect.

Furthermore, in this embodiment, the terminal device is a cellular phone9 by way of example. However, this is not restrictive and the presentinvention is applicable to a variety of portable terminal devices suchas PDAs, personal TVs, game machines, digital cameras, digital videocameras, and note-type personal computers. Furthermore, the presentinvention is also applicable to a variety of fixed terminal devices suchas cash dispensers, vending machines, monitors, and television receiversin addition to the portable terminal devices.

EMBODIMENT 2

The image display device according to Embodiment 2 of the presentinvention, display panel installed in the image display device, anddrive method thereof will be described.

In the display panel 2 installed in the image display device accordingto this embodiment, the pixel thin-film transistors TFT, gate lines G,and data lines D are connected as shown in FIG. 18 and the subpixels arestructured as shown in FIG. 19. The cross-sectional structures at thelines D-D′ and R-R′ in FIG. 19 are shown in FIGS. 20 and 21,respectively.

In the display panel 2 according to this embodiment, as shown in FIG.18, gate lines G1 to G7 extend in the column direction, namely in theY-axis direction, on the surface of the TFT substrate 2 a facing theliquid crystal layer 5LC, namely facing in the +Z direction. Data linesD1 to D13 extend in the row direction, namely in the X-axis direction,on the same surface of the TFT substrate 2 a.

In this embodiment, the gate lines G are angled, but extend in theY-axis direction while being angled multiple times. The gate lines G arearrayed in the X-axis direction. Furthermore, the data lines D areangled, but extend in the X-axis direction while being angled multipletimes. The data lines D are arrayed in the Y-axis direction. A subpixel4S (a left-eye pixel 4L or a right-eye pixel 4R) is placed near theintersection between a gate line G and a data line D. The same notationas in Embodiment 1 is used for clarify how a subpixel 4S is connected toa gate line G and a data line D. The letter P is followed by the numberaccompanying the data line D and then followed by the numberaccompanying the gate line G. In other words, the relationship of thedirections in which the gate lines G and data lines D extend to theimage separation direction of the lenticular lens 3 in the image displaydevice 1 according to this embodiment is different from that inEmbodiment 1.

In this embodiment, an expression “adjoining pixel pair” is used. Thisrefers to two subpixels 4S situated on either side of a data line D andconnected to the data line D between them. In other words, the subpixels4S constituting an adjoining pixel pair are supplied with the datapotential of video signals via the data line D interposed between them.For example, as shown in FIG. 18, two pixels P34 and P33 adjoining eachother in the Y-axis direction constitute an adjoining pixel pair 4PAIR1.Furthermore, two pixels P31 and P32 adjoining each other in the Y-axisdirection constitute an adjoining pixel pair 4PAIR2. In the followingexplanation, the adjoining pixel pairs 4PAIR1 and 4PAIR2 arecollectively referred to as 4PAIR for explaining the common structure.

The subpixels 4S constituting an adjoining pixel pair 4PAIR arecontrolled in switching operation via different gate lines G. In theadjoining pixel pair 4PAIR1 on the left in FIG. 19, the subpixel 4S onthe −Y side is controlled by the gate line G on the −X side, and thesubpixel 4S on the +Y side is controlled by the gate line G on the +Xside.

Then, adjoining pixel pairs 4PAIR adjacent to each other in theextending direction of the data lines D, namely in the X-axis direction,are connected to different data lines D, not to a common data line D.This is because the adjoining pixel pairs 4PAIR are adjacent to eachother in the X-axis direction with a shift in the Y-axis direction byone subpixel 4S. With this placement, the necessary number of wires canbe minimized, improving the aperture ratio.

Here, with reference to FIG. 18 again, the placement of subpixels inthis embodiment will be reviewed. First, attention is paid to anadjoining pixel pair comprising the pixels P31 and P32. For easierunderstanding, the above adjoining pixel pair is denoted by (P31, P32)in the following explanation. Then, this adjoining pixel pair (P31, P32)is adjoined by adjoining pixel pairs (P23, P22) and (P42, P43) in the +Xdirection. The adjoining pixel pair (P22, P23) uses the data line D2 asthe common data line. Here, “the common data line” means a shared dataline D placed between the subpixels constituting an adjoining pixelpair. The subpixels 4S constituting an adjoining pixel pair areconnected to the common data line placed between them and a datapotential supplied via the common data line D is written in them atgiven times. The adjoining pixel pair (P31, P32) uses the data line D3as the common data line and the adjoining pixel pair (P22, P23) uses thedata line D2 as the common data line; the adjoining pixel pairs (P31,P32) and (P22, P23) use different data lines D as their respectivecommon data lines D. Here, their respective common data lines areadjacent to each other. The layout of subpixels 4S in FIG. 19 shows thestructural relationship of, for example, the adjoining pixel pair (P34,P33) to pixels P25 and P45 adjacent to it in the +X direction shown inFIG. 18.

The adjoining pixel pair (P31, P32) is adjoined also by anotheradjoining pixel pair (P42, P43) in the +X direction. Those adjoiningpixel pairs also use different data lines as their respective commondata lines D.

Furthermore, the adjoining pixel pair (P23, P22) or adjoining pixel pair(P42, P43) is adjoined by an adjoining pixel pair (P34, P33) in the +Xdirection. Like the adjoining pixel pair (P31, P32), the adjoining pixelpair (P34, P33) uses the data line D3 as the common data line. In otherwords, the adjoining pixel pairs using the same data line D as thecommon data line are arranged in every other column of subpixels. Inother words, a data line D connected to adjoining pixel pairsconstituting a right-eye pixel 4R is not connected to adjoining pixelpairs constituting a left-eye pixel 4L.

In the adjoining pixel pair comprising the pixels P22 and P23, the pixelP22 on the −Y side of the common data line D2 is controlled by the gateline G2 situated on the −X side, and the pixel P23 on the +Y side of thecommon data line D2 is controlled by the gate line G3 situated on the +Xside. In other words, of the subpixels 4S of this adjoining pixel pairsituated above and below the common data line D, the subpixel 4S on the+Y side is connected to the gate line G on the +X side.

On the other hand, in the adjoining pixel pair comprising the pixels P31and P32, the pixel P32 on the −Y side of the common data line D3 isconnected to the gate line G2 situated on the +X side, and the pixel P31on the +Y side of the common data line D3 is connected to the gate lineG1 situated on the −X side. In other words, of the subpixels 4S of thisadjoining pixel pair situated above and below the common data line D,the subpixel 4S on the +Y side is connected to the gate line G on the −Xside. In the columns of subpixels adjacent in the +X direction, theadjoining pixel pairs of which the subpixel 4S on the +Y side iscontrolled by the gate line G on the −X side use the data line D on the−Y side as the common date line. Consequently, the same kind ofadjoining pixel pairs are arranged diagonally. In further other words,in this embodiment, the adjoining pixel pairs of which the subpixel onthe +Y side is connected to the gate line G on the −X side and theadjoining pixel pairs of which the subpixel on the +Y side is connectedto the gate line G on the +X side are arrayed.

The pixel thin-film transistors 4TFT provided in an adjoining pixel pair4PAIR have a double-gate structure in the shape of a horizontal U withtheir openings of the U shape facing each other. A charging capacitorelectrode CS2 shared by the two subpixels 4S constituting the adjoiningpixel pair 4PAIR is formed between the facing horizontal U-shaped pixelthin-film transistors 4TFT. A charging capacitor 4CS is formed betweenthe charging capacitor electrode CS2 and the silicon layer 4SI providedin each subpixel 4S.

This embodiment is the same in the other structure as theabove-described Embodiment 1.

The channel parts of pixel thin-film transistors 4TFT in the adjoiningpixel pairs 4PAIR1 and 4PAIR2 are parallel to the image separationdirection, namely the X-axis direction. The channel part is theoperation part of a pixel thin-film transistor 4TFT and should beuniform throughout the subpixels 4S. The data line D is inclined in adirection different from the image separation direction, namely theX-axis direction, in a layer above the channel region of pixel thin-filmtransistors 4TFT. Furthermore, the data line D is inclined in adirection different from the image separation direction above thecharging capacitor electrode CS2. As described above, the data lines Dextend in the X-axis direction while being angled multiple times in alayer above the pixel thin-film transistor 4TFT provided at the upperside of a parallelogram and the charging capacitor electrode CS2. Beingangled at the upper side of a parallelogram, the data line D isefficiently placed, improving the aperture ratio. Furthermore, since thechannel part of a pixel thin-film transistor 4TFT is parallel to theX-axis direction, uniform transistor properties can be obtained byorienting the channel parts of pixel thin-film transistors 4TFT equallyaccording to the excimer laser scanning direction in the case of usinglaser annealing to form a polysilicon thin film.

In this embodiment, the pixel thin-film transistors 4TFT controlling thesubpixels 4S of an adjoining pixel pair 4PAIR have a double-gatestructure and the channel part parallel to the X-axis direction. Thesource electrodes of the pixel thin-film transistors 4TFT areelectrically connected to the pixel electrodes 4PIX via contact holes4CONT2 for controlling the subpixel 4S on the +Y side and the subpixel4S on the −Y side, respectively. The contact holes 4CONT2 are formednear the pixel electrodes 4PIX to control for efficient placement. Insuch s structure, the drain electrode connected to a data line D is notparallel to the X-axis direction and, therefore, the data line D shouldbe angled. As shown in FIG. 19, in this embodiment, the data line D in alayer above the charging capacitor electrode CS2 is inclined in adirection different from the image separation direction so as toelectrically connect the drain electrodes of the pixel thin-filmtransistors 4TFT of an adjoining pixel pair 4PAIR along the shortestpath. The same wiring layout of inclined data line D can apply toconnect the drain electrode and data line D in every adjoining pixelpair 4PAIR. Therefore, the conditions upon writing into the subpixels 4Scan be maintained uniform.

As shown in FIGS. 19 and 21, the charging capacitor line CS iselectrically connected to the charging capacitor electrode CS2. Hence,the charging capacitor lines CS of the subpixels 4S constituting anadjoining pixel pair 4PAIR have the same potential. Since the upper andlower sides of parallelograms of an adjoining pixel pair 4PAIR face eachother, the common charging capacitor electrode CS2 serves to reduce thewasted space and efficiently reserve the area for forming the chargingcapacitor 4CS. Then, the aperture ratio can be increased compared withthe prior art and the transmittance can be improved.

Since the parallelogram pixels are adjacent to each other in the mannerthat the upper side of one subpixel 4S and the lower side of the othersubpixel 4S of an adjoining pixel pair 4PAIR face each other, provisionof the common charging capacitor electrode CS2 leads to increase in thearea for forming the pixel capacitor 4CLC. Then, the aperture ratio canbe increased compared with the prior art and the transmittance can beincreased.

The drive method, or display operation, of the above-described imagedisplay device 1 according to this embodiment will be describedhereafter. In this embodiment, the image display device 1 is driven bydot inversion drive. In the dot inversion drive, as shown in FIG. 22,the polarity of display data to be transferred is inverted with respectto a reference potential every data line, every gate line, and everyframe. The dot inversion drive is also called 1H1V inversion drive. Thisis because the polarity is inverted every data line arrayed in thehorizontal direction (H direction) and every gate line arrayed in thevertical direction (V direction).

The image display device 1 realizes the polarities of subpixels 4S asshown in FIG. 23 in a given frame as a result of dot inversion drive.First, as the gate line G1 is selected, display data of the positivepolarity are transferred to the data line D1 and a positive voltage iswritten in the pixel P11. On the other hand, display data of thenegative polarity are transferred to the data line D2. Similarly,display data of the positive polarity are transferred to the data linesD3, D5, D7, D9, D11, and D13, and display data of the negative polarityare transferred to the data lines D4, D6, D8, D10, and D12. Then, whenthe gate line G2 is selected, the polarities of the data lines are allinverted. In other words, display data of the negative polarity aretransferred to the data lines D1, D3, D5, D7, D9, D11, and D13, anddisplay data of the positive polarity are transferred to the data linesD2, D4, D6, D8, D10, and D12. Subsequently, when the gate line G3, G5,or G7 is selected, the same operation as when the gate line G1 isselected is conducted. When the gate line G4 is selected, the sameoperation as when the gate line G2 is selected is conducted. After thisframe is over, the polarity inversion is further conducted in the nextframe. In other words, when the gate line G1, G3, G5, or G7 is selected,display data of the negative polarity are transferred to the data linesD1, D3, D5, D7, D9, D11, and D13, and display data of the positivepolarity are transferred to the data lines D2, D4, D6, D8, D10, and D12.When the gate line G2, G4, or G6 is selected, display data of thepositive polarity are transferred to the data lines D1, D3, D5, D7, D9,D11, and D13, and display data of the negative polarity are transferredto the data lines D2, D4, D6, D8, D10, and D12.

A group of subpixels comprising right-eye pixels 4R has the polaritydistribution yielding the two-line dot inversion (2H1V dot inversion)effect, and so does a group of subpixels comprising left-eye pixels 4L.Consequently, the polarity distribution of an image to be viewed with aneye shows the polarity inverted every two data lines D2 arrayed in thehorizontal direction (H direction) or every gate line G arrayed in thevertical direction (V direction). The basic set of polarity distributionaccording to this embodiment consists of a total of 16 pixels, fourpixels in the X-axis direction and four pixels in the Y-axis direction.

This embodiment can prevent fluctuation in the potential of the chargingcapacitor line CS upon writing display data in the subpixels 4S. This isbecause not only the subpixels in which display data of the positivepolarity are written but also the subpixels in which display data of thenegative polarity are written are connected to the common chargingcapacitor electrode CS2 of an adjoining pixel pair 4PAIR in twoconsecutive gate line G selection periods. In this way, it is possibleto prevent the potential of the charging capacitor line CS fromfluctuating to one polarity and, then, reduce crosstalk occurring in theextending direction of the charging capacitor line CS and realize highquality image display. The structure according to this embodiment canrealize the two-line dot inversion effect and the effect of preventingfluctuation in the potential of the charging capacitor line CS whileusing conventional dot inversion drive, and allows the subpixels ofwhich the bases of parallelogram apertures are adjacent to each other tohave the same polarity. In this way, high quality image display can berealized at a low cost.

As shown in FIG. 24, the display panel 2 is placed with the long sideoriented in the X-axis direction and the short side oriented in theY-axis direction. Having the image separation direction in accord withthe X-axis direction, the display panel 2 is a display panelaccommodating landscape (wide-screen) display. In an example, thedisplay panel 2 has a screen resolution WVGA: 800 pixels in the X-axisdirection and 480 pixels in the Y-axis direction. As described above, aunit of display 4U comprises two subpixels corresponding to twoobserving points. One pixel comprises three units of display 4U and theunits of display 4U are colored in three colors. In such a case, thenumbers of data lines and gate lines used in the display unit 6 are asfollows: the number of data lines arrayed in the Y-axis direction is480×3+1=1441 and the number of gate lines arrayed in the X-axisdirection is 800×2+1=1601. Therefore, the display panel 2 shown in FIG.24 has data lines less than gate lines.

Furthermore, a drive IC 7 for controlling video signals is mounted on ashort side of the TFT substrate 2 a of the display panel 2. The outputof the drive IC 7 is connected to the data lines of the display unit 6.Generally, the output pin pitch of the drive IC 7 is smaller than thedata line pitch. Therefore, the wires extending from the output pins ofthe drive IC 7 to the data lines must be spread and, therefore, somedistance is necessary between the drive IC 7 and display unit 6. Thedistance between the display unit 6 and drive IC 7 can be reduced forthe same output pin pitch as the number of data lines to make connectionis smaller. In the case of the display unit 6 being used in thelandscape mode, the number of data lines can be reduced when the datalines extend horizontally, namely in the X-axis direction, to beconnected to the drive IC 7 at a short side of the display panel 2 thanwhen the data lines extend vertically to be connected to the drive IC 7at a long side of the display panel 2. Then, the data lines extendinghorizontally allows for a smaller frame. Furthermore, a smaller numberof data lines can reduce the necessary number of drive ICs 7, reducingthe cost and reducing the workload of the drive IC 7. Furthermore, amultiplexer circuit for data signals can be installed in the drive IC 7and a switching circuit capable of sorting data signals output from thedrive IC 7 in a time-sharing manner according to the operation of themultiplexer circuit can be provided on the TFT substrate 2 a. In thisway, the number of data signal wires output from the drive IC 7 to beconnected can further be reduced.

In this embodiment, a gate driver circuit for scanning the gate lines insequence is formed on the TFT substrate 2 a concurrently with the pixelthin-film transistors. In this way, the frame width of the display panel2 at the long side can be reduced. Furthermore, the display panel 2 canhave a smaller frame on each side by proving the drive IC 7 connected ata short side of the display panel 2 on a short side and integrating thegate driver circuit connected at a long side of the display panel 2. Thedisplay panel 2 having smaller frames is smaller in size and the numberof display panels 2 obtained from one mother board is increased,reducing the cost. Furthermore, integral formation of the subpixels andgate driver circuit on the TFT substrate 2 a leads to reduction in thenumber of parts of the driver circuit, reducing the cost and powerconsumption.

The screen resolution is not restricted to the above configuration.Apparently, a display panel 2 for N observing points having pixelscolored in K colors and a screen resolution of Mx pixels in the X-axisdirection and My pixels in the Y-axis direction can yield the aboveeffects provided that the relationship N×Mx<K×My is satisfied.

As described above, the data lines D connected to the adjoining pixelpairs 4PAIR constituting right-eye pixels 4R are not connected to theadjoining pixel pairs 4PAIR constituting left-eye pixels 4L. Therefore,with the odd-numbered data lines D1, D3, D5, D7, D9, D11 and D13 andeven-numbered data lines D2, D4, D6, D8, D10, and D12 being drivenindependently, the right-eye pixel 4R and left-eye pixel 4L can operateseparately to display a simplified parallax image. The three-dimensionalvisibility can be inspected simply by supplying signals to theeven-numbered data lines D or to the odd-numbered data lines Dseparately in the production process of placing the lenticular lens 3 onthe display panel 2. Then, the production yield in the subsequentprocess can be improved. The same signals can be supplied to theeven-numbered lines or to the odd-numbered lines at a time. The switchfor changeover of input signals between the even-numbered andodd-numbered lines can be formed on the TFT substrate 2 a concurrentlywith the pixel thin-film transistors 4TFT. In this way, the inspectiondevice can be simplified.

The image display device 1 according to this embodiment can be installedin a cellular phone 9 as shown in FIG. 15 in the same manner as inEmbodiment 1. The display panel 2 in this embodiment is characterized byhaving a narrow frame and, therefore, is favorably applicable toportable devices without imposing any limitation on the functionality,design, and operability required for portable devices.

EMBODIMENT 3

The image display device according to Embodiment 3 of the presentinvention and display panel installed in the image display device willbe described.

The subpixels of the display panel installed in the image display deviceaccording to this embodiment have the structures as shown in FIGS. 25and 26. The cross-sectional structure at the line D-D′ in FIGS. 25 and26 is shown in FIG. 27.

As shown in FIGS. 25 and 26, one charging capacitor line CS is providedin a subpixel 4S and crosses a virtual line R-R′ passing through thecenter of the subpixel 4S. The virtual line R-R′ is parallel to theY-axis direction and bisects the subpixel 4S in the X-axis direction.

In a subpixel 4S, the gate line G and charging capacitor line CS areinclined in directions different from the image separation direction.The gate line G and charging capacitor line CS have differentinclinations.

The gate lines G in the subpixels 4S arranged in the X-axis directionhave the same inclination. The charging capacitor lines CS are inclineddifferently in a unit of display 4U and inclined equally in an adjoiningpixel pair 4PAIR. Furthermore, the charging capacitor line CS is angledin different directions every subpixel 4S in the X-axis direction and inthe Y-axis direction so that the inclination is diversified in theX-axis direction and in the Y-axis direction.

This embodiment is the same in the other structure and operation as theabove-described Embodiment 1.

With the gate line G and charging capacitor line CS being inclineddifferently, the cycle of moire stripes appearing due to the lens arraypitch and wire array pitch is diversified in different directions,whereby the moire strips appearing due to the periodic structure of thedisplay panel 2 and image separating unit is made less visible,improving the display quality.

EMBODIMENT 4

The image display device according to Embodiment 4 of the presentinvention and display panel installed in the image display device willbe described.

The image display device 1 according to this embodiment has, as theimage separating unit, an optical element comprising a liquid crystalGRIN (gradient index) lens 301 as shown in FIG. 28.

As shown in FIG. 29, the liquid crystal molecules 50 between a controlsubstrate 302 and an opposite substrate 303 are subject to electricfield control by control electrodes 304, whereby the liquid crystal GRINlens 301 has a variable refractive index and yields the same effect as alens. When it is turned off, the liquid crystal GRIN lens 301 is subjectto no change in the refractive index and allows light to transmit as itis. When the liquid crystal GRIN lens 301 is turned on, the liquidcrystal molecules are radially oriented along the electrodes arranged instripes in the vertical direction of the panel, whereby the liquidcrystal GRIN lens 301 plays the role of a lens. A pair of controlelectrodes 304 forms a lens element 305. The lens elements 305 arearrayed in the plane of the liquid crystal GRIN lens 301. The lenselements 305 are placed in accordance with the units of display 4U.

This embodiment is the same in the other structure and operation as theabove-described Embodiment 1.

As shown in FIG. 29, some of the liquid crystal molecules 50 are notfully controlled by the control electrodes 304. Therefore, the liquidcrystal GRIN lens 301 has an optical performance profile dependent onthe liquid crystal orientation. Then, even in the case of using a GRIN(gradient index) lens, which is an electro-optical element using liquidcrystal, as the optical unit, the profile of refractive indexcorresponding to the lens concave part 32 is more uneven than theprofile of refractive index corresponding to the lens convex part 31because of the electric field created by the control electrodes 304.Furthermore, as with the above-described lenticular lens 3, besides theGRIN lens having the optical separation performance lower at theportions corresponding to the lens concave part 32, even with a liquidcrystal lens comprising a combination of a concave-convex substratehaving lens effect and liquid crystal molecules 50, the opticalseparation performance tends to deteriorate at steep, convex portionscorresponding to the lens concave part 32.

The liquid crystal GRIN lens 301 can yield partial lens effect in theplane of the liquid crystal GRIN lens 301 by selectively turning on/offthe lens elements 305. Consequently, the three-dimensional display (3Ddisplay) and two-dimensional display (2D display) can be mixed on thesame screen.

The display panel 2 according to this embodiment has a subpixel pitch Puof 150 μm and a liquid crystal layer thickness of 4 μm. The opticalelement comprising the liquid crystal GRIN lens 301 has a liquid crystallayer thickness of 50 μm. However, since this liquid crystal layerthickness is larger than 10 times the thickness of the liquid crystallayer of a conventional liquid crystal panel, the response issignificantly slow. Then, if the content requires frequent switchingbetween 3D display and 2D display on the same screen, some limitation isimposed on mixing 3D display and 2D display on the same screen bypartially turning on/off the lens elements 305 of the liquid crystalGRIN lens 301.

This embodiment can operate the left-eye pixel 4L and right-eye pixel 4Rin a unit of display 4U independently when the liquid crystal GRIN lens301 is on. Then, 3D display and 2D display can be mixed on the samescreen while keeping the liquid crystal GRIN lens 301 on. On the otherhand, when the liquid crystal GRIN lens 301 is off, high quality 2Ddisplay under no influence of the refractive index can be provided.

On the other hand, if the content does not require frequent switchingbetween 3D display and 2D display on the same screen, the lens elements305 of the liquid crystal GRIN lens 301 can be operated in part fordisplay, reducing the power consumption of the liquid crystal GRIN lens301.

EMBODIMENT 5

The image display device according to Embodiment 5 of the presentinvention and display panel installed in the image display device willbe described.

In the display panel 20 according to this embodiment, as shown in FIG.30, a pixel electrode 4PIX and a common electrode 4COM2 are provided onthe same substrate and an electric field nearly parallel to thesubstrate surface is applied to drive the liquid crystal molecules. Thepixel electrode 4PIX and common electrode 4COM2 are parallel to theupper and lower sides of a parallelogram subpixel.

FIG. 31 shows an example of a cross-sectional structure at the line F-F′in FIG. 30. The pixel electrode 4PIX and common electrode 4COM2 areformed with an insulating film 25 in-between, and the pixel electrode4PIX is provided with a slit electrode. Here, the common electrode 4COM2instead of the pixel electrode 4PIX can be provided with a slitelectrode. This embodiment is the same in the other structure andoperation as the above-described Embodiment 1.

Having the above configuration, this embodiment can provide an imagedisplay device with a larger angle of view.

Particularly, a conventional liquid crystal display element controls therubbing process on one substrate in one direction. Therefore, if eachsubpixel has an asymmetric structure with respect to the rubbingdirection, the display properties vary depending on the subpixel. Then,difference in display properties between observing points will appearparticularly in a three-dimensional display device.

The units of display 4U in this embodiment comprise subpixels of asingle outer shape, diminishing difference in the staggered structureand/or electric field profile structure between subpixels and reducingdifference in display properties between observing points caused bydifference in the subpixel shape. Furthermore, the subpixels areoriented uniformly so as to stabilize the liquid crystal orientationupon application of a voltage. In other words, difference in the imagequality between observing points can be diminished, and uniform imagescan be output at the observing points to provide high qualitythree-dimensional images. Furthermore, the subpixels of a single shapecontribute to stabilizing the orientation of liquid crystal moleculesthroughout the subpixels, reducing defective orientation and/or lightleakage and improving the contrast.

MODIFIED EMBODIMENT OF EMBODIMENT 5

The image display device according to a modified embodiment ofEmbodiment 5 of the present invention and display panel installed in theimage display device will be described.

In the display panel 2 according to this embodiment, as shown in FIG.32, a pixel electrode 4PIX and a common electrode 4COM2 are provided onthe same substrate and an electric field nearly parallel to thesubstrate surface is applied to drive the liquid crystal molecules. Thepixel electrode 4PIX and common electrode 4COM2 are parallel to theoblique sides of a parallelogram subpixel.

The liquid crystal molecules of subpixels 4S adjacent to each other inthe Y-axis direction are oriented in directions different from eachother by an electric field from the pixel electrode 4PIX. The liquidcrystal molecules of subpixels arranged in the Y-axis direction formdifferent domains, reducing change in hue when seen in a diagonaldirection.

In this embodiment, a positive liquid crystal material having a positivedielectric constant anisotropy (Δ∈>0) is employed and the rubbingdirection on the side to the TFT substrate 2 a is set to the −Ydirection or the +Y direction. Then, the liquid crystal molecules 50 areoriented with their long axis nearly in parallel to the Y-axis directionin the initial state.

The liquid crystal material is not restricted to positive materials andcan be negative materials having a negative dielectric constantanisotropy (Δ∈<0). When a negative liquid crystal material is used, therubbing direction is set to the −X direction or the +X direction. Then,the liquid crystal molecules 50 are oriented with their long axis nearlyin parallel to the X-axis direction. It is difficult for a negativeliquid crystal material to rise in the long axis direction with respectto the electric field in the direction perpendicular to the substratesurface. The liquid crystal molecules above the electrodes are entrainedby the liquid crystal molecules rotating in a substrate plane andoriented, whereby the transmittance above the electrodes can beimproved. Furthermore, difference in brightness between above theelectrodes and between the electrodes is diminished, whereby 3D moirecaused by this difference in brightness can be reduced.

This embodiment is the same in the other structure and operation as theabove-described image display device 1 of Embodiment 5.

This embodiment employs a domain cycle of two rows due to angling and acolor filter cycle of three rows. Then, multi-domain compensation occursin every six rows. The subpixels having the same color and shape arerepeated in a cycle of six rows, 6×Py. When this cycle is enlarged,unevenness becomes more visible and the image quality deteriorates.Therefore, subjective assessment revealed that the desirable pixel pitchPu is equal to or smaller than 150 μm. In other words, it is desirablethat the subpixel pitch in the Y-axis direction is equal to or smallerthan 50 μm.

Various embodiments and modifications are available to the presentinvention without departing from the broad sense of spirit and scope ofthe present invention. The above-described embodiments are given forexplaining the present invention and do not confine the scope of thepresent invention. In other words, the scope of the present invention isset forth by the scope of claims, not by the embodiments. Variousmodifications made within the scope of claims and scope of significanceof the invention equivalent thereto are considered to fall under thescope of the present invention.

The above embodiments are partially or entirely described as in thefollowing subjunction, but not limited thereto.

(Subjunction 1)

An image display device, comprising:

a display panel in which units of display including at least a pixeldisplaying a first observing point image and a pixel displaying a secondobserving point image are arranged in a matrix; and

an optical distributer for distributing light emitted from the pixeldisplaying the first observing point image and pixel displaying thesecond observing point image in directions different from each other ina first direction, wherein

the pixel displaying the first observing point image and pixeldisplaying the second observing point image are adjacent to each otherin the first direction;

the units of display are arranged in rows extending in the firstdirection and in columns extending in a second direction perpendicularto the first direction;

a shielding unit is provided around an aperture of the pixel displayingthe first observing point image and an aperture of the pixel displayingthe second observing point image;

the aperture of the pixel displaying the first observing point image andaperture of the pixel displaying the second observing point imageinclude a first region where the apertures overlap with each other inthe second direction and a second region that is a remaining region;

a total aperture width in the second direction of the aperture of thepixel displaying the first observing point image and aperture of thepixel displaying the second observing point image in the first region isa first aperture width;

an aperture width in the second direction of the aperture of the pixeldisplaying the first observing point image and aperture of the pixeldisplaying the second observing point image in the second region is asecond aperture width;

a third region where two of the units of display adjacent to each otherin the first direction overlap with each other in the second directionis provided, and a total aperture width in the second direction of thetwo units of display in the third region is a third aperture width;

the aperture of the pixel displaying the first observing point image andaperture of the pixel displaying the second observing point image eachcomprises a shape that is at least point-symmetric and notline-symmetric;

centers of the apertures are shifted in the second direction withrespect to a line parallel to the first direction and passing through acenter of the unit of display, and the aperture of the pixel displayingthe first observing point image and aperture of the pixel displaying thesecond observing point image are point-symmetric about the center of theunit of display; and

the third aperture width is different from the first aperture width.

(Subjunction 2)

The image display device according to Subjunction 1, wherein:

the third aperture width is smaller than the first aperture width.

(Subjunction 3)

The image display device according to Subjunction 1 or 2, wherein:

the optical distributer comprises an alternate structure at least in thefirst direction comprising regions of high separation performance andregions of low separation performance in distributing light from thepixel displaying the first observing point image and pixel displayingthe second observing point image in directions different from eachother; and

the regions of high separation performance extend from the aperture ofthe pixel displaying the first observing point image to the aperture ofthe pixel displaying the second observing point image.

(Subjunction 4)

The image display device according to any one of Subjunction 1 to 3,wherein:

the optical distributer comprises a lenticular lens sheet in whichconvex parts and concave parts of cylindrical lenses are alternatelyarranged in the first direction; and

the convex parts of cylindrical lenses are provided at positionscorresponding to the first region and the concave parts of cylindricallenses are provided at positions corresponding to the third region.

(Subjunction 5)

The image display device according to any one of Subjunction 1 to 3,wherein:

the optical distributer comprises a refractive index distributed lenscomprising a pair of substrates with liquid crystal in-between; and

a pair of electrodes provided to the substrates is provided at positionscorresponding to the third region.

(Subjunction 6)

The image display device according to any one of Subjunction 1 to 5,wherein:

the pixel displaying the first observing point image and pixeldisplaying the second observing point image are subpixels, and theapertures are enclosed by data lines, gate lines and charging capacitorelectrodes;

the subpixels of the display panel are arranged in an array of adjoiningpixel pairs each comprising two subpixels provided on either side of oneof the gate lines and adjacent to each other in the second direction asa basic unit;

a switcher of one of the two subpixels and a switcher of the other ofthe two subpixels are controlled by the gate line interposed between andshared by the two subpixels and connected to different ones of the datalines;

one electrode of the switchers forms a capacitor together with thecharging capacitor electrode; and

the charging capacitor electrode is electrically connected to a chargingcapacitor line provided at least in a boundary region between thesubpixels in the unit of display.

(Subjunction 7)

The image display device according to any one of Subjunction 1 to 5,wherein:

the pixel displaying the first observing point image and the pixeldisplaying the second observing point image are subpixels, and theapertures are enclosed by data lines, gate lines and charging capacitorelectrodes;

the subpixels of the display panel are arranged in an array of adjoiningpixel pairs each comprising two subpixels provided on either side of oneof the data lines and adjacent to each other in the second direction asa basic unit;

a switcher of one of the two subpixels and a switcher of the other ofthe two subpixels are connected to the data line interposed between andshared by the two subpixels and controlled by different ones of the gatelines;

one electrode of the switchers forms a capacitor together with thecharging capacitor electrode;

the charging capacitor electrode is provided at least in a boundaryregion between the subpixels of the adjoining pixel pair; and

N charging capacitor lines electrically connected to the chargingcapacitor electrode each crosses at least one of virtual lines parallelto the second direction and dividing a width of the subpixel into N+1equal parts in the first direction at the aperture.

(Subjunction 8)

The image display device according to any one of Subjunction 1 to 7,wherein:

the display panel comprises a substrate at least provided with a pair ofparallel electrodes and a liquid crystal layer interposed between thesubstrate and an opposite substrate; and

the pair of parallel electrodes is arranged in the second direction andliquid crystal molecules of the liquid crystal layer are driven by anelectric field created between the pair of parallel electrodes.

(Subjunction 9)

The image display device according to Subjunction 8, wherein:

the pair of parallel electrodes comprises transparent electrodescomprising at least two layers formed with an insulating filmin-between; and

one layer of the transparent electrodes is provided with a slitelectrode.

(Subjunction 10)

The image display device according to Subjunction 9, wherein:

the slit electrode is a transparent electrode on a side to the liquidcrystal layer.

(Subjunction 11)

A display panel in which units of display including at least a pixeldisplaying a first observing point image and a pixel displaying a secondobserving point image are arranged in a matrix, wherein:

the units of display are arranged in rows extending in a first directionin which the pixel displaying the first observing point image and pixeldisplaying the second observing point image are adjacent to each otherand in columns extending in a second direction perpendicular to thefirst direction;

a shielding unit is provided around an aperture of the pixel displayingthe first observing point image and an aperture of the pixel displayingthe second observing point image;

the aperture of the pixel displaying the first observing point image andaperture of the pixel displaying the second observing point imageinclude a first region where the apertures overlap with each other inthe second direction and a second region that is a remaining region;

a total aperture width in the second direction of the aperture of thepixel displaying the first observing point image and aperture of thepixel displaying the second observing point image in the first region isa first aperture width;

an aperture width in the second direction of the aperture of the pixeldisplaying the first observing point image and aperture of the pixeldisplaying the second observing point image in the second region is asecond aperture width;

a third region where two of the units of display adjacent to each otherin the first direction overlap with each other in the second directionis provided, and a total aperture width in the second direction of thetwo units of display in the third region is a third aperture width;

the aperture of the pixel displaying the first observing point image andaperture of the pixel displaying the second observing point image eachcomprises a shape that is at least point-symmetric and notline-symmetric;

centers of the apertures are shifted in the second direction withrespect to a line parallel to the first direction and passing through acenter of the unit of display, and the aperture of the pixel displayingthe first observing point image and aperture of the pixel displaying thesecond observing point image are point-symmetric about the center of theunit of display; and

the third aperture width is different from the first aperture width.

(Subjunction 12)

A terminal device in which the image display device according to any oneof Subjunction 1 to 10 is installed.

Having described and illustrated the principles of this application byreference to one or more preferred embodiments, it should be apparentthat the preferred embodiments may be modified in arrangement and detailwithout departing from the principles disclosed herein and that it isintended that the application be construed as including all suchmodifications and variations insofar as they come within the spirit andscope of the subject matter disclosed herein.

LEGEND

-   -   1 image display device    -   2 display panel    -   2 a TFT substrate    -   2 b opposite substrate    -   3 lenticular lens    -   3 a cylindrical lens    -   31 lens convex part    -   32 lens concave part    -   33 first axis    -   34 second axis    -   301 liquid crystal GRIN lens    -   302 control substrate    -   303 opposite substrate    -   304 control electrode    -   305 lens element    -   4U unit of display    -   4S subpixel    -   4R right-eye pixel    -   4L left-eye pixel    -   4P pixel    -   41 boundary between subpixels    -   42 boundary between units of display    -   4PAIR1, 4PAIR2, 4PAIR adjoining pixel pair    -   4PIX pixel electrode    -   4TFT pixel thin-film transistor    -   4CLC pixel capacitor    -   4CS charging capacitor    -   CS charging capacitor line    -   CS2 charging capacitor electrode    -   4CONT1, 4CONT2 contact hole    -   4COM opposite electrode    -   4COM2 common electrode    -   4SI silicon layer    -   5LC liquid crystal layer    -   50 liquid crystal molecules    -   6 display unit    -   7 drive IC    -   8 flexible substrate    -   9 cellular phone    -   11 polarizing plate    -   15 backlight    -   16 line presenting the light beam direction    -   17 line presenting the center axis of image separation    -   18 TFT substrate rubbing direction    -   19 opposite substrate rubbing direction    -   21 first insulating layer    -   22 second insulating layer    -   23 third insulating layer    -   24 fourth insulating layer    -   25 insulating film    -   55L left eye    -   55R right eye    -   60 black matrix    -   G, G1, . . . , G13 gate line    -   D, D1, . . . , D13 data line    -   RED red filter    -   GREEN green filter    -   BLUE blue filter    -   SP spot diameter    -   1011 vertical direction (the longitudinal direction of a        cylindrical lens)    -   1012 horizontal direction (the arrangement direction of a        cylindrical lens)    -   1003 a cylindrical lens    -   1041 first observing point pixel    -   1042 second observing point pixel    -   1070 wiring    -   1075 aperture    -   1076 shielding unit

1. An image display device, comprising: a display panel in which unitsof display including at least a pixel displaying a first observing pointimage and a pixel displaying a second observing point image are arrangedin a matrix; and an optical distributer for distributing light emittedfrom said pixel displaying the first observing point image and pixeldisplaying the second observing point image in directions different fromeach other in a first direction, wherein said pixel displaying the firstobserving point image and pixel displaying the second observing pointimage are adjacent to each other in said first direction; said units ofdisplay are arranged in rows extending in said first direction and incolumns extending in a second direction perpendicular to said firstdirection; a shielding unit is provided around an aperture of said pixeldisplaying the first observing point image and an aperture of said pixeldisplaying the second observing point image; the aperture of said pixeldisplaying the first observing point image and aperture of said pixeldisplaying the second observing point image include a first region wherethe apertures overlap with each other in said second direction and asecond region that is a remaining region; a total aperture width in saidsecond direction of the aperture of said pixel displaying the firstobserving point image and aperture of said pixel displaying the secondobserving point image in said first region is a first aperture width; anaperture width in said second direction of the aperture of said pixeldisplaying the first observing point image and aperture of said pixeldisplaying the second observing point image in said second region is asecond aperture width; a third region where two of said units of displayadjacent to each other in said first direction overlap with each otherin said second direction is provided, and a total aperture width in saidsecond direction of said two units of display in said third region is athird aperture width; the aperture of said pixel displaying the firstobserving point image and aperture of said pixel displaying the secondobserving point image each comprises a shape that is at leastpoint-symmetric and not line-symmetric; centers of the apertures areshifted in said second direction with respect to a line parallel to saidfirst direction and passing through a center of said unit of display,and the aperture of said pixel displaying the first observing pointimage and aperture of said pixel displaying the second observing pointimage are point-symmetric about the center of said unit of display; andsaid third aperture width is different from said first aperture width.2. The image display device according to claim 1, wherein: said thirdaperture width is smaller than said first aperture width.
 3. The imagedisplay device according to claim 1, wherein: said optical distributercomprises an alternate structure at least in said first directioncomprising regions of high separation performance and regions of lowseparation performance in distributing light from said pixel displayingthe first observing point image and pixel displaying the secondobserving point image in directions different from each other; and saidregions of high separation performance extend from the aperture of saidpixel displaying the first observing point image to the aperture of saidpixel displaying the second observing point image.
 4. The image displaydevice according to claim 1, wherein: said optical distributer comprisesa lenticular lens sheet in which convex parts and concave parts ofcylindrical lenses are alternately arranged in said first direction; andsaid convex parts of cylindrical lenses are provided at positionscorresponding to said first region and said concave parts of cylindricallenses are provided at positions corresponding to said third region. 5.The image display device according to claim 1, wherein: said opticaldistributer comprises a refractive index distributed lens comprising apair of substrates with liquid crystal in-between; and a pair ofelectrodes provided to said substrates is provided at positionscorresponding to said third region.
 6. The image display deviceaccording to claim 1, wherein: said pixel displaying the first observingpoint image and pixel displaying the second observing point image aresubpixels, and said apertures are enclosed by data lines, gate lines andcharging capacitor electrodes; said subpixels of said display panel arearranged in an array of adjoining pixel pairs each comprising twosubpixels provided on either side of one of said gate lines and adjacentto each other in said second direction as a basic unit; a switcher ofone of said two subpixels and a switcher of the other of said twosubpixels are controlled by said gate line interposed between and sharedby said two subpixels and connected to different ones of said datalines; one electrode of said switchers forms a capacitor together withsaid charging capacitor electrode; and said charging capacitor electrodeis electrically connected to a charging capacitor line provided at leastin a boundary region between said subpixels in said unit of display. 7.The image display device according to claim 1, wherein: said pixeldisplaying the first observing point image and said pixel displaying thesecond observing point image are subpixels, and said apertures areenclosed by data lines, gate lines and charging capacitor electrodes;said subpixels of said display panel are arranged in an array ofadjoining pixel pairs each comprising two subpixels provided on eitherside of one of said data lines and adjacent to each other in said seconddirection as a basic unit; a switcher of one of said two subpixels and aswitcher of the other of said two subpixels are connected to said dataline interposed between and shared by said two subpixels and controlledby different ones of said gate lines; one electrode of said switchersforms a capacitor together with said charging capacitor electrode; saidcharging capacitor electrode is provided at least in a boundary regionbetween said subpixels of said adjoining pixel pair; and N chargingcapacitor lines electrically connected to said charging capacitorelectrode each crosses at least one of virtual lines parallel to saidsecond direction and dividing a width of said subpixel into N+1 equalparts in said first direction at said aperture.
 8. The image displaydevice according to claim 1, wherein: said display panel comprises asubstrate at least provided with a pair of parallel electrodes and aliquid crystal layer interposed between said substrate and an oppositesubstrate; and said pair of parallel electrodes is arranged in saidsecond direction and liquid crystal molecules of said liquid crystallayer are driven by an electric field created between said pair ofparallel electrodes.
 9. The image display device according to claim 8,wherein: said pair of parallel electrodes comprises transparentelectrodes comprising at least two layers formed with an insulating filmin-between; and one layer of said transparent electrodes is providedwith a slit electrode.
 10. The image display device according to claim9, wherein: said slit electrode is a transparent electrode on a side tosaid liquid crystal layer.
 11. A display panel in which units of displayincluding at least a pixel displaying a first observing point image anda pixel displaying a second observing point image are arranged in amatrix, wherein: said units of display are arranged in rows extending ina first direction in which said pixel displaying the first observingpoint image and pixel displaying the second observing point image areadjacent to each other and in columns extending in a second directionperpendicular to said first direction; a shielding unit is providedaround an aperture of said pixel displaying the first observing pointimage and an aperture of said pixel displaying the second observingpoint image; the aperture of said pixel displaying the first observingpoint image and aperture of said pixel displaying the second observingpoint image include a first region where the apertures overlap with eachother in said second direction and a second region that is a remainingregion; a total aperture width in said second direction of the apertureof said pixel displaying the first observing point image and aperture ofsaid pixel displaying the second observing point image in said firstregion is a first aperture width; an aperture width in said seconddirection of the aperture of said pixel displaying the first observingpoint image and aperture of said pixel displaying the second observingpoint image in said second region is a second aperture width; a thirdregion where two of said units of display adjacent to each other in saidfirst direction overlap with each other in said second direction isprovided, and a total aperture width in said second direction of saidtwo units of display in said third region is a third aperture width; theaperture of said pixel displaying the first observing point image andaperture of said pixel displaying the second observing point image eachcomprises a shape that is at least point-symmetric and notline-symmetric; centers of the apertures are shifted in said seconddirection with respect to a line parallel to said first direction andpassing through a center of said unit of display, and the aperture ofsaid pixel displaying the first observing point image and aperture ofsaid pixel displaying the second observing point image arepoint-symmetric about the center of said unit of display; and said thirdaperture width is different from said first aperture width.
 12. Aterminal device in which the image display device according to claim 1is installed.